remove viewport pin left over from touchpad handling

The renderer pinned a viewport dragged into sublime's past-end room. With
scroll_past_end off there is no such room: sublime clamps to bottom_y, so the
trigger can only fire against a stale anchor, which following() already
resolves on the next frame.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Architecture.md

@@ -196,11 +196,6 @@ the same way, and scrolling down clamps to the anchor `bottom_y` returns, which
 it. A one-row scroll lands exactly on the tolerance boundary, so one Up closes the gate
 and one Down re-opens it.
 
-**Pinning waits for rest.** The renderer pins a viewport dragged into sublime's past-end
-room on a terminal too idle to draw a frame, but only once two ticks agree it has come to
-rest: macOS keeps scrolling after the fingers lift, and a hard `set_viewport_position`
-against that momentum yanks the view back for as long as the glide lasts.
-
 ### How colour is actually drawn
 
 `view.add_regions(key, regions, scope)` can only name a **scope**. It cannot take a
@@ -367,9 +362,10 @@ palette and restyles open terminals in place.
 
 **Stamped on every terminal view** by `vterm_initialize_view`: `vterm_view` (the marker
 every context and hook keys off), `is_widget`, `color_scheme` (the generated scheme),
-`syntax` (the empty one), `scroll_past_end`, `scroll_context_lines`, and a list of
-disables — `gutter`, `highlight_line`, `word_wrap`, `auto_complete`, `draw_white_space`,
-`draw_indent_guides`, `spell_check`, `translate_tabs_to_spaces`, `command_mode` (which
+`syntax` (the empty one), `scroll_past_end` (off — the view never scrolls below the last
+line), `scroll_context_lines`, and a list of disables — `gutter`, `highlight_line`,
+`word_wrap`, `auto_complete`, `draw_white_space`, `draw_indent_guides`, `spell_check`,
+`translate_tabs_to_spaces`, `command_mode` (which
 defuses Vintage mode inside a terminal). The view is also set scratch, so closing it never
 prompts to save.
 

tests/test_render.py

@@ -587,8 +587,6 @@ terminal.viewport_y = 400
 command = make_command(terminal.view)
 fold_end = terminal.view.text_point(3, 0) - 1
 
-terminal.view.settings().set("scroll_past_end", True)
-
 stream.feed("\x1b[?1049h")
 command.sync_alt_fold(terminal)
 assert terminal.view.folds == [(0, fold_end)], terminal.view.folds
@@ -610,7 +608,6 @@ assert terminal.viewport_y == 60, terminal.viewport_y
 stream.feed("\x1b[?1049l")
 command.sync_alt_fold(terminal)
 assert terminal.view.folds == [], terminal.view.folds
-assert terminal.view.settings().get("scroll_past_end") is True, "left untouched"
 
 # without scrollback there is nothing to fold
 terminal, stream = make_terminal(rows=5, cols=20)

vterm/render.py

@@ -218,8 +218,9 @@ class VtermRenderCommand(sublime_plugin.TextCommand):
         if want and view.fold(sublime.Region(0, end)) and entering:
             # entering collapses the layout; a stale viewport anchor would
             # stop the follow-scroll gate from re-engaging. re-asserting a
-            # disturbed fold keeps the anchor: apps repaint the boundary row
-            # every scroll, and resetting per repair thrashes the poller
+            # disturbed fold keeps the anchor instead: apps repaint the
+            # boundary row on every scroll, and resetting per repair would
+            # drop the user's place each time
             terminal.viewport_y = 0
 
     def sync_cursor_style(self, terminal):

vterm/terminal.py

@@ -280,7 +280,6 @@ class Terminal:
 
         def renderer():
             """Own the emulator: parse, then ask sublime to redraw, once per tick."""
-            settled_y = None
             while True:
                 # a hidden tab is not drawn at all: the screen keeps the state
                 # and one render on unhide catches the view up. The tick stays at
@@ -298,21 +297,6 @@ class Terminal:
                         # due first: _need_to_render consumes the cursor move it reports
                         if self.is_render_due() and self._need_to_render():
                             self.view.run_command("vterm_render")
-                            # a frame can move the viewport: a sample from
-                            # before it says nothing about coming to rest
-                            settled_y = None
-                        else:
-                            # the wheel can drag the screen off the top into
-                            # sublime's past-end room; a frame undoes that, and
-                            # an idle terminal draws none. Pinning while the
-                            # view is still gliding fights the scroll's
-                            # momentum, which reads as shaking, so wait for two
-                            # ticks to agree that it has come to rest
-                            y = self.view.viewport_position()[1]
-                            if y == settled_y and self.viewport_y < y:
-                                from .render import request_scroll  # module-level import would cycle
-                                request_scroll(self.view, self)
-                            settled_y = y
                     self._sync_wheel_flag()
                     if done[0] or not self.is_hosted():
                         LOG.debug("[renderer] stops")