Unexpected re-rendering

[valentijnnieman]

I wanted to document some findings around dash-renderer and the possibly unnecessary re-rendering I think it sometimes does.

I've noticed that the TreeContainer's shouldComponentUpdate method does not do what we think it does - even when returning false it still renders. Logging the result of the logic in shouldComponentUpdate and logging in render() looks like this:

I have also noticed that the callbacks are being called twice upon initializing, as demonstrated in this test: https://github.com/plotly/dash-core-components/blob/62e90491c67a79edcfb0bdbdf2f5fa134efd791e/test/test_integration.py#L898 which could also be caused by unexpected re-rendering behaviour.

[ZeCarlosCoutinho]

I had a problem of callbacks being called twice even after initializing. When I click a button, there is a first call to the callback, and after some seconds, a second call to the callback is triggered. However, n_clicks = 1

[alexcjohnson]

Not sure if this is still an issue, but moving it to dash so we don't lose it.

[BSd3v]

I'd be curious to know if this is satisfied by the adjustments in Dash 3.