MPL Event Handling Doc Example not fully functioning

I tried the example from the MPL event handling docs: a bar chart with draggable bars (“extra credit” version). This works fine in QT5Agg backend, but doesn’t fully work in Jupyter Lab (v3.0.7) with ipympl (v0.7.0). The plot displays fine, and I can see that click and drag events are being received by the widget, but during drag, the bars vanish. In fact, if in the click handler I include a color change:

        self.rect.set(animated=True,color='red')

Then I can see a faint red outline after the bar is “dropped” in the correct location (see below). So clearly the click/drag/release events are working, but the bar drawing during and after drag via draw_artist and blit are not.

[ianhi]

I think what you’re running into now is this issue from core matplotlib: https://github.com/matplotlib/matplotlib/issues/19116

Unfortunately no one has figured out a solution yet, your thoughts are of course welcome!

[jdtsmith]

Another bit of debugging. If I artificially limit movements to be relatively quite large (dropping all motion events that are “too small”), and move slowly it works just fine: