Before the problem was using the pseudoclass 'active'. Now, by using
a css class instead, it works.
Also, before when clicking the button twice (activate/deactivate) - it
was always on focus (and therefore always grey). Also fixed.
Now this is a standard behaviour of TableWidget.
Removed also table related help information from general
Hilfe-zu-dieser-Seite help.
[ALPHA VERSION]: minor issue to be fixed:
button color not toggling correctly when opening help then settings
(and way round)
Before row color was changing from selected-blue to grey, although row
was still selected, which was somehow confusing for the user.
Now color stays blue.