I have been using Ubuntu 18.04 for a while and everything went well. But now I noticed something weird. The shortcut for hiding all tools windows in IDEA stopped working. I checked my keyboard shortcuts to see if I have any collisions, but I didn't find any.
Then I used "Show keyboard layout" to visualize my keyboard and I noticed, that the combination ctrl+shift+f12, is not registered. I see that that ctrl and shift are pressed, but not f12. The same thing happens for f9, f10 and f11. But it works fine with f1-f8 (I see all three of them being pressed in "show keyboard layout") and any other keyboard combinations.
I use the shortcut ctrl+shift+f12 quite extensively and I would prefer not changing the shortcut combination if possible.