Colour assignment for containers is unnecessarily restrictive

[crankycoder]

While I appreciate that someone spent the time to assign a nice colour palette for containers, it is a problem for people (namely me) who are severely colour blind.

I need to be able to make the colours wildly different for me to differentiate them - especially when the container colour only seems to draw a thin line at the bottom of the tab chrome.

Please do keep a default palette, but allow users to select arbitrary RGB colours to override the defaults.

[Madis0]

Duplicate of #391

[Softvision-CristinaBadescu]

Indeed, the same idea seems to be discussed in #391. I'm gonna close this one, but please provide any additional feedback there if you think it's necessary.