FIX: handle the change detection differently for multicursor

tacaswell · ksunden · commit b88acdbba96f · 2023-02-07T17:54:59.000-06:00
There is not a singular canvas
diff --git a/lib/matplotlib/widgets.py b/lib/matplotlib/widgets.py
@@ -2110,6 +2110,12 @@ def clear(self, event):
             return
         if self.useblit:
             for canvas, info in self._canvas_infos.items():
+                # someone has switched the canvas on us!  This happens if
+                # `savefig` needs to save to a format the previous backend did
+                # not support (e.g. saving a figure using an Agg based backend
+                # saved to a vector format).
+                if canvas is not canvas.figure.canvas:
+                    continue
                 info["background"] = canvas.copy_from_bbox(canvas.figure.bbox)
 
     def onmove(self, event):
