Colour disappears after resetting colours in multi-block inspector

Hi,

I have observed the following strange behaviour in Paraview 5.6.0 Linux binaries.

To reproduce, open the can.ex2, select the first object in the pipeline, switch to Solid Color in the Active Variable Controls, go to multi-block inspector and:

  • List item Right click on block ID 1, chose Set Block Color, chose a color and apply. The colour is not applied. Now repeat the process but this time aim your right click on the leftmost circle and the colour will be applied.

  • List item Time to reset the colour back to the original value. The same issue as above applies, however, once you click on the circle and reset the colour, the colour will turn 100% black and there will be no way to revert this.

Tested on OpenSuse 13.1 and RedHat 7.3

Regards,
Lukasz

Looks like there is a bug here in this menu. Uses the icon on the left of the block instead.

https://gitlab.kitware.com/paraview/paraview/merge_requests/1621
https://gitlab.kitware.com/paraview/paraview/issues/18620