Thanks!
I tried to do the change to submit a patch but I found some problems.
I cloned the repository, and right after it I did a mvn verify and found some test failing (4 always and 1 sometimes)
[...]
Is there any special supported development environment?
No.
It seems strange to have these failures.
Those tests are "unstable", as they're dealing (poorly) with async stuff, they may fail or succeed depending on a part of luck. Unfortunately, it didn't manage to become anyone's top priority task to fix them at the moment...
You can ignore them; or if you can fix them so they're stable, that would be a very welcome contribution ;)
I have debugged the ColorTest and found what's happening (the red value of the RGB needs to be changed from 56 to 55 due to rounding issues and the text needs to be larger than just "a" for both tests otherwise the box with the color seems to be not rendered properly in its position) but I suspect that changing it will break on CI.
Can you please open a bug about this one? I guess we can hack the test to be more flexible, or look at a different pixel that's not affected by rounding.
Do you know what could be happening?
Basically, nothing too bad. Don't feel blocked in your contribution for the activeWhen stuff because of it.