Keep scrollback under a full-screen scroll region

Sublime recreates every TextCommand instance whenever any plugin loads,
which dropped colored_lines and restarted the region key counter: old
overlays were never erased and keys were reused. RenderState now lives on
terminal.render_state, which survives reloads.

Architecture.md

@@ -52,10 +52,11 @@ Generated at runtime, not in the repo: `Packages/User/vterm/vterm.hidden-color-s
   `Char` carrying the extra `linefeed` field.
 - **`SchemeManager`** (`scheme.py`) — module singleton `scheme_manager`. Owns the
   generated scheme file and the mapping from colour combination to scope name.
-- **`VtermRenderCommand`** (`render.py`) — Sublime keeps **one command instance per
-  view**, so its `colored_lines`, `_row_cache`, `_key_counter`, the scrollback chunk
-  bookkeeping (`_archived_chunks`, `_open_rows`, `_open_chunk`, `_trimmed`) and
-  `_lastrow` are that view's render state.
+- **`VtermRenderCommand`** (`render.py`) — the per-frame logic. Sublime rebuilds every
+  `TextCommand` instance whenever any plugin loads, so the view's render state
+  (`RenderState`: `colored_lines`, `row_cache`, `key_counter`, the scrollback chunk
+  bookkeeping `archived_chunks`, `open_rows`, `open_chunk`, `trimmed`) lives on
+  `terminal.render_state`, bound as `self.state` at the top of each `run()`.
 
 ### Commands
 
@@ -74,10 +75,9 @@ Generated at runtime, not in the repo: `Packages/User/vterm/vterm.hidden-color-s
 | `vterm_cleanup` | `VtermCleanupCommand` | renderer, on process exit |
 | `vterm_close` | `VtermCloseCommand` | nothing — available for a user keybinding |
 | `vterm_clear_undo_stack` / `vterm_noop` | `commands.py` | internal |
-| `vterm_scroll` / `vterm_mouse_click` | `mouse.py` | mousemap, `drag_select` interception |
+| `vterm_scroll` / `vterm_mouse_press` / `vterm_mouse_release` | `mouse.py` | mousemap |
 
-Two application-wide `EventListener`s: `VtermCoreEventListener` (`listeners.py`) and
-`VtermMouseEventListener` (`mouse.py`).
+One application-wide `EventListener`: `VtermCoreEventListener` (`listeners.py`).
 
 
 ---

Default (OSX).sublime-mousemap

@@ -11,6 +11,13 @@
         "args": {"up": false},
         "context": [{"key": "vterm_view.wheel_captured", "operand": true}]
     },
+    {
+        // press reports the click, release reports the drag
+        "button": "button1",
+        "press_command": "vterm_mouse_press",
+        "command": "vterm_mouse_release",
+        "context": [{"key": "vterm_view.mouse_reporting", "operand": true}]
+    },
     {
         // press_command: sublime's own button3 binding is a column drag_select,
         // which would clear the selection before a release command could read it

README.md

@@ -79,10 +79,11 @@ or turns it off. Copy/paste use the normal Sublime keys, and pastes are
 bracketed when the app asks for it. Copying re-joins soft-wrapped lines. The
 middle button pastes the current selection straight into the app, X11-style,
 without going near the clipboard; it does nothing when nothing is selected. The
-wheel scrolls the view normally; while the app tracks the mouse the wheel and
-left click go to it instead, and on the alternate screen without tracking each
-wheel tick sends arrow keys (alternate scroll, as kitty/iTerm2 do — this is
-what scrolls Claude Code's fullscreen UI before it enables mouse reporting).
+wheel scrolls the view normally; while the app tracks the mouse the wheel, clicks
+and drags go to it instead (Claude Code's own mouse selection and copy work as in
+kitty), and on the alternate screen without tracking each wheel tick sends arrow
+keys (alternate scroll, as kitty/iTerm2 do — this is what scrolls Claude Code's
+fullscreen UI before it enables mouse reporting).
 Sublime raises no wheel event at all for the trackpad (sublime_text#1838): set
 a utility such as [LinearMouse](https://linearmouse.app/) to discrete scrolling
 for Sublime Text and it arrives as wheel notches like any other. A notch sends the
@@ -149,15 +150,16 @@ terminal protocols — see `Architecture.md`.
   into the view: an app that does not echo (vim in normal mode) would otherwise
   leave the character behind. `on_modified` in `vterm/listeners.py` remains the
   fallback for IME and composed input.
-- `vterm/mouse.py` — SGR mouse reporting (wheel, click) when the app enables
+- `vterm/mouse.py` — SGR mouse reporting (wheel, click, drag) when the app enables
   tracking; native selection and scrolling otherwise. The trackpad is not
   handled: it reaches no mousemap on macOS and is converted to wheel notches
   outside the plugin.
 
 Supported: alt screen (1049), synchronized output (2026), bracketed paste (2004),
-mouse tracking 1000/1002/1003 + SGR 1006 (wheel and left click are reported; no
-drag, no right button; the middle button pastes the selection instead of being
-reported), focus events (1004),
+mouse tracking 1000/1002/1003 + SGR 1006 (wheel and left button are reported; a
+drag arrives as one motion at release, since Sublime raises none; no right
+button; the middle button pastes the selection instead of being reported),
+focus events (1004),
 xterm modifyOtherKeys (`CSI > 4 ; n m`, for the modified keys with no
 unambiguous legacy encoding: enter, tab, backspace, space), cursor styles (DECSCUSR —
 block/bar and blink/steady via the view's caret settings; underline falls back

main.py

@@ -26,8 +26,8 @@ from .vterm.commands import (
 )
 from .vterm.listeners import VtermCoreEventListener
 from .vterm.mouse import (
-    VtermMouseClickCommand,
-    VtermMouseEventListener,
+    VtermMousePressCommand,
+    VtermMouseReleaseCommand,
     VtermScrollCommand,
 )
 from .vterm.scheme import build_startup_schemes

tests/test_emulator.py

@@ -141,6 +141,11 @@ def run_case(char_by_char):
     assert len(screen.history) == 1, (tag, len(screen.history))
     assert screen.history[0][0].data == "a", tag
 
+    # an explicit full-screen scroll region still feeds scrollback
+    proc, screen, stream = make(10, 3)
+    feed(stream, "\x1b[1;3ra\r\nb\r\nc\r\nd", char_by_char)
+    assert len(screen.history) == 1, (tag, len(screen.history))
+
     # ED 3 clears history and fires callback
     cleared = []
     proc = FakeProcess()

tests/test_render.py

@@ -9,9 +9,10 @@ from _bootstrap import FakeProcess
 import sublime
 from vterm.commands import VtermKeypressCommand
 from vterm.emulator import VtScreen, VtStream
-from vterm.mouse import VtermMouseClickCommand, VtermScrollCommand
+from vterm.mouse import VtermMousePressCommand, VtermMouseReleaseCommand, VtermScrollCommand
 from vterm.render import (
     CHUNK,
+    RenderState,
     VtermRenderCommand,
     focus_cursor,
     following,
@@ -171,6 +172,8 @@ def make_command(terminal):
     # run() itself sets _scheme, but these tests call its helpers directly
     command = VtermRenderCommand(terminal.view)
     command._scheme = terminal.scheme
+    terminal.render_state = RenderState()
+    command.state = terminal.render_state
     return command
 
 
@@ -282,7 +285,7 @@ assert terminal.view.text.startswith("RED..red..green"), repr(terminal.view.text
 assert len(painted) == 2, painted
 
 # keys are unique per view and recorded so decolorize_line can erase them
-assert sorted(terminal.view.regions) == sorted(command.colored_lines[0]), \
+assert sorted(terminal.view.regions) == sorted(command.state.colored_lines[0]), \
     "colored_lines must track exactly the keys that were added"
 command.decolorize_line(0)
 assert terminal.view.regions == {}, "decolorize must erase every key it added"
@@ -290,6 +293,29 @@ assert terminal.view.regions == {}, "decolorize must erase every key it added"
 print("colorize tests passed (arithmetic offsets, scope batching, key bookkeeping)")
 
 
+# sublime rebuilds every TextCommand instance whenever any plugin loads; the
+# bookkeeping lives on the terminal so a rebuilt command still erases what the
+# old one painted, and its keys never collide with keys still in use
+terminal, stream = make_terminal(rows=3, cols=20)
+terminal.view = FakeView()
+command = make_command(terminal)
+stream.feed("\x1b[31mred line\x1b[0m\r\nplain")
+command.update_lines(None, terminal)
+terminal.screen.dirty.clear()
+assert terminal.view.regions, "the red row must be painted"
+# a reload: new command, same terminal
+reloaded = VtermRenderCommand(terminal.view)
+reloaded._scheme = terminal.scheme
+reloaded.state = terminal.render_state
+stream.feed("\x1b[H\x1b[2Kgone")
+reloaded.update_lines(None, terminal)
+assert terminal.view.regions == {}, \
+    "a rebuilt command must erase the old overlay: {}".format(terminal.view.regions)
+assert reloaded.next_key() != "vterm#1", "keys must continue, not restart"
+
+print("reload tests passed (render state survives a rebuilt command)")
+
+
 # rows that leave the screen have their colours merged onto shared per-(scope,
 # chunk) keys once the chunk closes; per-row keys would otherwise accumulate for
 # the whole session, and merging every frame would re-send the whole chunk
@@ -318,10 +344,10 @@ command = make_command(terminal)
 stream.feed("".join("\x1b[31mr{}\x1b[0m\r\n".format(i) for i in range(300)))
 command.update_lines(None, terminal)
 terminal.screen.dirty.clear()
-assert set(command._archived_chunks) == {0}, command._archived_chunks
+assert set(command.state.archived_chunks) == {0}, command.state.archived_chunks
 command.trim_history(None, terminal)
 assert "vterm@0@vterm.red.default" not in terminal.view.regions, "trimmed chunk key left behind"
-assert 0 not in command._archived_chunks
+assert 0 not in command.state.archived_chunks
 assert "vterm@1@vterm.red.default" in terminal.view.regions, "boundary chunk must survive"
 
 print("scrollback archive tests passed (chunk keys bounded, trim erases whole chunks)")
@@ -600,19 +626,31 @@ terminal.view.window_to_text = lambda xy: 0
 window = FakeWindow(active=object())
 terminal.view.window = lambda: window
 stream.feed("\x1b[?1002h\x1b[?1006h")
-click = VtermMouseClickCommand.__new__(VtermMouseClickCommand)
-click.view = terminal.view
+mouse_press = VtermMousePressCommand.__new__(VtermMousePressCommand)
+mouse_press.view = terminal.view
+mouse_release = VtermMouseReleaseCommand.__new__(VtermMouseReleaseCommand)
+mouse_release.view = terminal.view
 event = {"x": 0, "y": 0, "button": 1}
 
-click.run(None, event)
+mouse_press.run(None, event)
 assert window.active_view() is terminal.view, "click did not focus the tab"
+mouse_release.run(None, event)
 assert terminal.process.written == "", repr(terminal.process.written)
 
-# once focused, the same click reports as before
-click.run(None, event)
+# once focused, press and release at one cell report a click
+mouse_press.run(None, event)
+mouse_release.run(None, event)
 assert terminal.process.written == "\x1b[<0;1;1M\x1b[<0;1;1m", repr(terminal.process.written)
 
-print("click focus tests passed (first click focuses only, then reports)")
+# a release elsewhere reports one drag motion first
+terminal.process.writes.clear()
+terminal.view.text = "r0    \nr1    \nr2    \nr3    \nr4    \n"
+mouse_press.run(None, event)
+terminal.view.window_to_text = lambda xy: terminal.view.text_point(2, 4)
+mouse_release.run(None, event)
+assert terminal.process.written == "\x1b[<0;1;1M\x1b[<32;5;3M\x1b[<0;5;3m", repr(terminal.process.written)
+
+print("click tests passed (first click focuses only; press, drag and release report)")
 
 
 # entering the alt screen folds the scrollback away (kitty hides it); leaving

vterm/emulator.py

@@ -442,7 +442,9 @@ class VtScreen(pyte.Screen):
 
     def index(self):
         """Line feed; at the bottom of the primary screen the top row goes to scrollback."""
-        if not self.alternate_buffer_mode and self.cursor.y == self.lines - 1 and self.margins is None:
+        # a region spanning the whole screen (CSI 1;<lines> r) is no region
+        full = self.margins is None or self.margins == (0, self.lines - 1)
+        if not self.alternate_buffer_mode and self.cursor.y == self.lines - 1 and full:
             self.push_lines_into_history(1)
         super().index()
 

vterm/listeners.py

@@ -88,7 +88,7 @@ class VtermCoreEventListener(sublime_plugin.EventListener):
         """Answer the contexts the mousemap needs"""
         # keymap contexts are native "setting.x"; mousemaps do not evaluate
         # those the same way, so their flags still need the hook
-        if key not in ("vterm_view", "vterm_view.wheel_captured"):
+        if key not in ("vterm_view", "vterm_view.wheel_captured", "vterm_view.mouse_reporting"):
             return None
         value = view.settings().get(key, False)
         if operator == sublime.OP_EQUAL:

vterm/mouse.py

@@ -13,6 +13,8 @@ from .utils import settings
 # SGR button numbers for the wheel; 64 is the "scroll" bit plus direction
 WHEEL_UP = 64
 WHEEL_DOWN = 65
+# button 0 with the "moved while held" bit
+MOTION = 32
 
 
 def send_scroll(terminal, up, lines, cell=None):
@@ -36,7 +38,7 @@ def _event_to_cell(view, terminal, event, clamp=False):
     """Map a mouse event to 1-based (col, row) on the live screen, or None.
 
     Clamping pulls a point above or below the screen onto the nearest row: the
-    wheel still belongs to the app there, a click does not."""
+    wheel and a release still belong to the app there, a press does not."""
     pt = view.window_to_text((event["x"], event["y"]))
     row, col = view.rowcol(pt)
     row -= terminal.offset
@@ -48,46 +50,60 @@ def _event_to_cell(view, terminal, event, clamp=False):
     return (min(col, screen.columns - 1) + 1, row + 1)
 
 
-class VtermMouseEventListener(sublime_plugin.EventListener):
-    """Hands button-1 clicks to the app, but only while it tracks the mouse."""
-
-    def on_text_command(self, view, name, args):
-        """Replace drag_select with a mouse report; other click variants stay native."""
-        terminal = Terminal.from_id(view.id())
-        if not terminal:
-            return
-        if not terminal.screen.mouse_reporting_enabled():
-            # leave selection, caret and scrolling to sublime
-            return
-        if name == "drag_select" and args and args.get("event", {}).get("button") == 1 and len(args) == 1:
-            return ("vterm_mouse_click", {"event": args["event"]})
-
-
-class VtermMouseClickCommand(sublime_plugin.TextCommand):
-    """Reports a click to the app, or focuses the tab if it was not active."""
+class VtermMousePressCommand(sublime_plugin.TextCommand):
+    """Bound to button 1 in the mousemap while the app tracks the mouse."""
 
     def run(self, edit, event):
-        """Focus the tab on the first click, report press and release after that."""
+        """Focus an inactive tab; else report the press and remember its cell."""
         terminal = Terminal.from_id(self.view.id())
         if not terminal:
             return
+        terminal.mouse_press = None  # a release may not come: the context can drop mid-drag
         window = self.view.window()
         if window and window.active_view() != self.view:
-            # we replaced drag_select, which is what focuses the group; this
-            # click only focuses, as clicking an unfocused terminal window does
+            # the mousemap binding displaces drag_select, which is what focuses
+            # the group; this click only focuses, as in a terminal window
             window.focus_view(self.view)
             return
         cell = _event_to_cell(self.view, terminal, event)
         if cell is None:
             return
+        terminal.mouse_press = cell
         terminal.send_mouse(0, cell[0], cell[1], pressed=True)
-        terminal.send_mouse(0, cell[0], cell[1], pressed=False)
+        # native drag_select only previews the selection while dragging; the
+        # app gets the real one at release
+        self.view.run_command("drag_select", {"event": event})
 
     def want_event(self):
         """Ask sublime for the click coordinates."""
         return True
 
 
+class VtermMouseReleaseCommand(sublime_plugin.TextCommand):
+    """Reports the release, after one drag motion when the button came up elsewhere.
+
+    Sublime raises no motion events, so a drag reaches the app as a single
+    move to the release cell; an app's selection then spans press to release.
+    The native preview selection goes, leaving the app's own highlight."""
+
+    def run(self, edit, event):
+        """Report motion and release for the pending press, if any."""
+        terminal = Terminal.from_id(self.view.id())
+        if not terminal or terminal.mouse_press is None:
+            return
+        cell = _event_to_cell(self.view, terminal, event, clamp=True)
+        if cell != terminal.mouse_press:
+            terminal.send_mouse(MOTION, cell[0], cell[1], pressed=True)
+        terminal.send_mouse(0, cell[0], cell[1], pressed=False)
+        terminal.mouse_press = None
+        self.view.sel().clear()
+        self.view.run_command("vterm_show_cursor", {"scroll": False})
+
+    def want_event(self):
+        """Ask sublime for the release coordinates."""
+        return True
+
+
 class VtermScrollCommand(sublime_plugin.TextCommand):
     """Bound to scroll wheel in the mousemap while the app tracks the mouse or is on the alt screen."""
 

vterm/render.py

@@ -116,34 +116,49 @@ def ensure_position(view, edit, row, col=0):
         view.insert(edit, line_region.end(), " " * (col - lastcol))
 
 
-class VtermRenderCommand(sublime_plugin.TextCommand):
-    """Draws the screen into the view. Sublime keeps one instance per view, so
-    the caches below are that view's render state."""
+class RenderState:
+    """A view's render bookkeeping, kept on its Terminal.
 
-    def __init__(self, *args, **kwargs):
-        """Set up this view's render caches."""
-        super().__init__(*args, **kwargs)
-        # the terminal's current SchemeManager; set at the top of each run()
-        self._scheme = None
+    Sublime rebuilds every TextCommand instance of every view whenever any
+    plugin module loads. State held on the command is lost then: the overlays
+    already in the view become untracked, so a row rewrite no longer erases
+    them, and the key counter restarts and hands out keys still in use.
+    """
+
+    def __init__(self):
+        """Empty bookkeeping, for a view that has nothing painted yet."""
+        # view row -> region keys painted on it
         self.colored_lines = {}
         # view row -> (segments, lf) as last rendered; the dirty set is only a
         # repaint hint, so most dirty rows are identical frame to frame
-        self._row_cache = {}
-        self._key_counter = 0
+        self.row_cache = {}
+        self.key_counter = 0
         # chunk ordinal -> scopes it holds a key for; ordinals are view row +
         # rows trimmed so far, so they survive trim_history renumbering
-        self._archived_chunks = {}
+        self.archived_chunks = {}
         # rows waiting for their chunk to close, and the chunk they belong to
-        self._open_rows = []
-        self._open_chunk = None
-        self._trimmed = 0
+        self.open_rows = []
+        self.open_chunk = None
+        self.trimmed = 0
+
+
+class VtermRenderCommand(sublime_plugin.TextCommand):
+    """Draws the screen into the view. Holds nothing a frame depends on: the
+    view's bookkeeping is `terminal.render_state` (see RenderState)."""
+
+    def __init__(self, *args, **kwargs):
+        """Per-instance scratch only; the render state is bound in run()."""
+        super().__init__(*args, **kwargs)
+        # the terminal's current SchemeManager and RenderState; set at the top of each run()
+        self._scheme = None
+        self.state = None
         self._lastrow = 0
         self._applied_cursor_style = None
 
     def next_key(self):
         """A region key unique to this view; per-row keys would collide after trim_history renumbers rows"""
-        self._key_counter += 1
-        return "vterm#{}".format(self._key_counter)
+        self.state.key_counter += 1
+        return "vterm#{}".format(self.state.key_counter)
 
     def ensure_row(self, edit, row):
         """Row-existence check for the hot path, tracking the last row in python"""
@@ -158,6 +173,9 @@ class VtermRenderCommand(sublime_plugin.TextCommand):
         if not terminal:
             return
         self._scheme = terminal.scheme
+        if terminal.render_state is None:
+            terminal.render_state = RenderState()
+        self.state = terminal.render_state
 
         screen = terminal.screen
         # the caret and the tab name are the user's; an unfocused terminal leaves
@@ -256,16 +274,16 @@ class VtermRenderCommand(sublime_plugin.TextCommand):
         screen = terminal.screen
 
         view.replace(edit, sublime.Region(0, view.size()), "")
-        for line in list(self.colored_lines):
+        for line in list(self.state.colored_lines):
             self.decolorize_line(line)
-        for chunk, scopes in self._archived_chunks.items():
+        for chunk, scopes in self.state.archived_chunks.items():
             for scope in scopes:
                 view.erase_regions(chunk_key(chunk, scope))
-        self._archived_chunks.clear()
-        self._open_rows = []
-        self._open_chunk = None
-        self._trimmed = 0
-        self._row_cache.clear()
+        self.state.archived_chunks.clear()
+        self.state.open_rows = []
+        self.state.open_chunk = None
+        self.state.trimmed = 0
+        self.state.row_cache.clear()
         terminal.offset = 0
         screen.history.clear()
         if wipe_screen:
@@ -312,9 +330,9 @@ class VtermRenderCommand(sublime_plugin.TextCommand):
         # the dirty set is a repaint hint, not a diff: most dirty rows come
         # back identical, and rewriting one costs an edit plus its region churn
         rendered = (segments, lf)
-        if self._row_cache.get(line) == rendered:
+        if self.state.row_cache.get(line) == rendered:
             return
-        self._row_cache[line] = rendered
+        self.state.row_cache[line] = rendered
 
         by_scope = {}
         needed = 0
@@ -343,7 +361,7 @@ class VtermRenderCommand(sublime_plugin.TextCommand):
     def colorize_line(self, line, line_start, by_scope):
         """Lay the colour overlays for one row, one add_regions per scope."""
         view = self.view
-        keys = self.colored_lines.setdefault(line, []) if by_scope else None
+        keys = self.state.colored_lines.setdefault(line, []) if by_scope else None
         for scope, spans in by_scope.items():
             key = self.next_key()
             view.add_regions(key, [sublime.Region(line_start + a, line_start + b) for a, b in spans], scope)
@@ -351,21 +369,21 @@ class VtermRenderCommand(sublime_plugin.TextCommand):
 
     def decolorize_line(self, line):
         """Drop a row's colour overlays before it is rewritten or erased."""
-        if line in self.colored_lines:
-            for key in self.colored_lines[line]:
+        if line in self.state.colored_lines:
+            for key in self.state.colored_lines[line]:
                 self.view.erase_regions(key)
-            del self.colored_lines[line]
+            del self.state.colored_lines[line]
 
     def archive_rows(self, rows):
         """Queue rows that left the screen for their chunk's merge."""
         for row in rows:
-            if row not in self.colored_lines:
+            if row not in self.state.colored_lines:
                 continue
-            chunk = (row + self._trimmed) // CHUNK
-            if chunk != self._open_chunk:
+            chunk = (row + self.state.trimmed) // CHUNK
+            if chunk != self.state.open_chunk:
                 self.flush_chunk()
-                self._open_chunk = chunk
-            self._open_rows.append(row)
+                self.state.open_chunk = chunk
+            self.state.open_rows.append(row)
 
     def flush_chunk(self):
         """Merge the queued rows onto shared per-(scope, chunk) keys.
@@ -376,8 +394,8 @@ class VtermRenderCommand(sublime_plugin.TextCommand):
         whole set, so merging every frame would be quadratic in CHUNK.
         """
         view = self.view
-        rows, chunk = self._open_rows, self._open_chunk
-        self._open_rows = []
+        rows, chunk = self.state.open_rows, self.state.open_chunk
+        self.state.open_rows = []
         if not rows:
             return
 
@@ -385,12 +403,12 @@ class VtermRenderCommand(sublime_plugin.TextCommand):
         stale = []
         scope_of = self._scheme.scope
         for row in rows:
-            keys = self.colored_lines.pop(row, None)
+            keys = self.state.colored_lines.pop(row, None)
             if not keys:
                 continue
             stale += keys
             # the segments that were painted, straight from the row cache
-            segments = self._row_cache[row][0]
+            segments = self.state.row_cache[row][0]
             start = view.line(view.text_point(row, 0)).begin()
             for _, a, b, fg, bg, style in segments:
                 if is_default_run(fg, bg, style):
@@ -398,7 +416,7 @@ class VtermRenderCommand(sublime_plugin.TextCommand):
                 scope = scope_of(fg, bg, style)
                 grouped.setdefault(scope, []).append(sublime.Region(start + a, start + b))
 
-        scopes = self._archived_chunks.setdefault(chunk, set())
+        scopes = self.state.archived_chunks.setdefault(chunk, set())
         for scope, regions in grouped.items():
             key = chunk_key(chunk, scope)
             if scope in scopes:
@@ -431,7 +449,7 @@ class VtermRenderCommand(sublime_plugin.TextCommand):
         while row > cursor_row:
             line_region = view.line(view.text_point(row, 0))
             text = view.substr(line_region)
-            if len(text.strip()) == 0 and (row not in self.colored_lines or not self.colored_lines[row]):
+            if len(text.strip()) == 0 and (row not in self.state.colored_lines or not self.state.colored_lines[row]):
                 row = row - 1
             else:
                 break
@@ -445,7 +463,7 @@ class VtermRenderCommand(sublime_plugin.TextCommand):
             trailing_region = sublime.Region(line_region.begin() + rev_wcwidth(text, cursor.x) + 1, line_region.end())
             if not trailing_region.empty() and len(view.substr(trailing_region).strip()) == 0:
                 view.erase(edit, trailing_region)
-                self._row_cache.pop(row, None)
+                self.state.row_cache.pop(row, None)
 
     def trim_history(self, edit, terminal):
         """Hold the view to scrollback_size rows, and drop rows below the screen."""
@@ -459,8 +477,8 @@ class VtermRenderCommand(sublime_plugin.TextCommand):
             m = max(lastrow + 1 - n, math.ceil(n / 10))
             for line in range(m):
                 self.decolorize_line(line)
-            self.colored_lines = {k - m: v for (k, v) in self.colored_lines.items()}
-            self._row_cache = {k - m: v for (k, v) in self._row_cache.items() if k >= m}
+            self.state.colored_lines = {k - m: v for (k, v) in self.state.colored_lines.items()}
+            self.state.row_cache = {k - m: v for (k, v) in self.state.row_cache.items() if k >= m}
             top_region = sublime.Region(0, view.full_line(view.text_point(m - 1, 0)).end())
             view.erase(edit, top_region)
             terminal.offset -= m
@@ -468,12 +486,12 @@ class VtermRenderCommand(sublime_plugin.TextCommand):
 
             # chunks wholly above the cut go; the boundary chunk drops the
             # regions the erase collapsed to empty
-            self._trimmed += m
-            cut = self._trimmed // CHUNK
-            for chunk in [c for c in self._archived_chunks if c < cut]:
-                for scope in self._archived_chunks.pop(chunk):
+            self.state.trimmed += m
+            cut = self.state.trimmed // CHUNK
+            for chunk in [c for c in self.state.archived_chunks if c < cut]:
+                for scope in self.state.archived_chunks.pop(chunk):
                     view.erase_regions(chunk_key(chunk, scope))
-            for scope in self._archived_chunks.get(cut, ()):
+            for scope in self.state.archived_chunks.get(cut, ()):
                 key = chunk_key(cut, scope)
                 view.add_regions(key, [r for r in view.get_regions(key) if not r.empty()], scope)
 
@@ -482,7 +500,7 @@ class VtermRenderCommand(sublime_plugin.TextCommand):
             for line in view.lines(tail_region):
                 row = view.rowcol(line.begin())[0]
                 self.decolorize_line(row)
-                self._row_cache.pop(row, None)
+                self.state.row_cache.pop(row, None)
             view.erase(edit, tail_region)
 
 

vterm/terminal.py

@@ -101,6 +101,7 @@ class Terminal:
         """State only; the pty and the threads come up in start()."""
         self.view = view
         self.scheme = scheme
+        self.render_state = None
         # process.isalive() costs two waitpid syscalls; UI hooks read this instead
         self.alive = True
         self.default_title = ""
@@ -120,6 +121,8 @@ class Terminal:
         # guards the queue/flag handoff between send_string and the drain thread
         self._send_lock = threading.Lock()
         self._wheel_captured = False
+        self._mouse_reporting = False
+        self.mouse_press = None  # cell of the pending button-1 press, for the release report
         self._scroll_pending = False
         self.pending_clear = False
         self.pending_clear_screen = False
@@ -328,7 +331,7 @@ class Terminal:
                             if frames >= UNDO_CLEAR_FRAMES:
                                 frames = 0
                                 self.view.run_command("vterm_clear_undo_stack")
-                    self._sync_wheel_flag()
+                    self._sync_mouse_flags()
                     if done[0] or not self.is_hosted():
                         LOG.debug("[renderer] stops")
                         break
@@ -424,12 +427,16 @@ class Terminal:
                 continue
             self.process.write(string)
 
-    def _sync_wheel_flag(self):
-        """Publish whether the app owns the wheel, for the mousemap context."""
-        captured = self.screen.mouse_reporting_enabled() or self.screen.alternate_buffer_mode
+    def _sync_mouse_flags(self):
+        """Publish whether the app owns the wheel and the mouse, for the mousemap contexts."""
+        reporting = self.screen.mouse_reporting_enabled()
+        captured = reporting or self.screen.alternate_buffer_mode
         if captured != self._wheel_captured:
             self._wheel_captured = captured
             self.view.settings().set("vterm_view.wheel_captured", captured)
+        if reporting != self._mouse_reporting:
+            self._mouse_reporting = reporting
+            self.view.settings().set("vterm_view.mouse_reporting", reporting)
 
     def send_focus(self, focused):
         """Report focus gain or loss, when the app asked for it (?1004)."""