embedding plots get triggered during long brush strokes

[kevinyamauchi]

I noticed that sometimes when painting with long brush strokes, the plot update gets triggered.

To reproduce, I think it's something like:

1. paint one stroke and release the mouse button
2. In less than one second (the debounce duration), start painting again
3. if you don't complete the paint stroke before 1s after (1), I think the drawing gets triggered.

We can consider using the labels_update event instead. I think that gets triggered during the draw of the paint stroke.

[kevinyamauchi]

I tried switching to the labels_update event and it helps for all cases except for when the user stops moving the mouse while painting (i.e., pauses in place while holding the mouse button down). We may have to figure out a way to check both that painting has stopped before triggering the redraw and cancel the redraw if the user starts moving the mouse again.