Blittering in jupyter renderer

[tpaviot]

When a shape is clicked in jupyter, it gets selected and its color is set to yellow. I noticed a blittering on Chrome/Windows, shape color changes from gray to yellow at least two times.

[tpaviot]

Same thing on FF/Win

[jf---]

hi @tpaviot this might be due to how event handling in the traits library is handled for every time a property is updated, the state is changed from js -> python, and its easy to get a situation where a redraw event is invoked