Merge pull request matplotlib#17480 from anntzer/rsa

FIX: Regenerate background when RectangleSelector active-flag is set back on.

Author: tacaswell

lib/matplotlib/widgets.py

@@ -1456,8 +1456,21 @@ def update_background(self, event):
         """Force an update of the background."""
         # If you add a call to `ignore` here, you'll want to check edge case:
         # `release` can call a draw event even when `ignore` is True.
-        if self.useblit:
+        if not self.useblit:
+            return
+        # Make sure that widget artists don't get accidentally included in the
+        # background, by re-rendering the background if needed (and then
+        # re-re-rendering the canvas with the visible widget artists).
+        needs_redraw = any(artist.get_visible() for artist in self.artists)
+        with ExitStack() as stack:
+            if needs_redraw:
+                for artist in self.artists:
+                    stack.callback(artist.set_visible, artist.get_visible())
+                    artist.set_visible(False)
+                self.canvas.draw()
             self.background = self.canvas.copy_from_bbox(self.ax.bbox)
+        if needs_redraw:
+            self.update()
 
     def connect_default_events(self):
         """Connect the major canvas events to methods."""