Fix browser back-button use for clickable-plots

[Donnyvdm]

Currently if a user clicks on a dot in any of the clickable plots, the app navigates to the matrix page. However, if the user then uses the back-button in the browser, the app redirects the user to the matrix page again.

The bug seems to be caused by the 'ClickData' value not being cleared upon page navigation and the redirect callback gets triggered every time the plot loads.
Possible solutions:

• Remember the previous state of the clickdata and only navigate if the new click is different from the previous one. This will introduce a bug by preventing navigation if a user clicks a dot -> hits the back button -> clicks the same dot again.
• Clear the ClickData value upon page navigation. If ClickData can be used as an Output in a callback, it could use the dcc.Location as input and be cleared every time the url changes.
• Check the Dash community forums if anyone has had the same problem

[Donnyvdm]

@howard-lightfoot @wendyyang I cannot reproduce this bug, could you try to see if it's fixed for you too? Maybe fixed with the dash update?

[Donnyvdm]

The bug occurs only in firefox with the following sequence:

1. visit page with clickable plot
2. click one of the data points
3. hit the browser back-button
4. hover over the plot again

[Donnyvdm]

The source seems to be deep inside the dash framework and dcc.Location element (and how it interacts with the browser), so it is currently not worth the effort of fixing it.