Fix redraw handling (regression bug)

In DistributedProofreaders#238, binding of button-1 (left-click) created a regression
that didn't fire redraws on click properly.

Fixes DistributedProofreaders#613

src/guiguts/maintext.py

@@ -3215,24 +3215,28 @@ def _autoscroll_start(
     ) -> None:
         """When Button-1 is pressed, turn mouse-drag monitoring on"""
         self._autoscroll_active = True
+        self._on_change()
 
     def _autoscroll_stop(
         self, event: tk.Event  # pylint: disable=unused-argument
     ) -> None:
         """When Button-1 is released, turn mouse-drag monitoring off"""
         self._autoscroll_active = False
+        self._on_change()
 
     def _autoscroll_start_peer(
         self, event: tk.Event  # pylint: disable=unused-argument
     ) -> None:
         """When Button-1 is pressed, turn mouse-drag monitoring on"""
         self._autoscroll_peer_active = True
+        self._on_change()
 
     def _autoscroll_stop_peer(
         self, event: tk.Event  # pylint: disable=unused-argument
     ) -> None:
         """When Button-1 is released, turn mouse-drag monitoring off"""
         self._autoscroll_peer_active = False
+        self._on_change()
 
     def _autoscroll_main(self, event: tk.Event) -> None:
         """Auto-scroll the main text view when dragging beyond widget border"""
@@ -3297,6 +3301,7 @@ def _autoscroll_callback(self, textwidget: tk.Text, event: tk.Event) -> None:
             delay = 100
 
         self.after(delay, lambda: callback(event))
+        self._on_change()
 
 
 def img_from_page_mark(mark: str) -> str: