Renoise 2.7.2 under Linux. When in record mode in pattern editor, pressing Ctrl + F3 does nothing. It should cut the current whole pattern and clear it. Shortcuts under “Preferences” shows Ctrl + F3 as “Copy and Clear Pattern”, but it does not work.
does the pattern editor have focus? (brackets around borders?)
Middle mouse click in the pattern editor region to be sure.
Sure, it has the focus.
Just to be sure, I don’t mean the red border when edit mode is on, but 4 separate little brackets. Anyway, I don’t have 2.7.2 installed anymore, so can’t check. Works in 2.8.
Yes, the 4 little brackets so exist.
Where to get the 2.8 version? 
2.8 is still currently in beta testing phase.
If you’re a registered user, you can access beta versions in the Backstage area.
[CTRL] + [F3] should definitely be working in 2.7.2 anyway. I’m sure we must have some other guys using 2.7.2 on Linux who can confirm this?
Has to be something else going on here, I think. Is it possible you might have some other application installed which is stealing the shortcut keys on a system-wide level?
Have you tried to map [CTRL] + [F3] to a totally different function in Renoise, just to make sure that the keys themselves are actually working normally?
Have you tried to map some completely different shortcut keys to the clear pattern function, just to make sure that the function itself is working normally?
Would be great if you could test this a bit more and let us know what you discover.
Do any of your F-keys work? F9 to top of pattern for example?
OSX and maybe others sometimes have the F-keys to work as the Fn (computer function) keys by default and this needs to be changed/Fn key also held down. It may be possible some variants of Linux have done similar (although it feels unlikely.)
I can confirm Ctrl+F3 works as expected here on 2.7.2 Win32.
Right! I had “Override Window Manager Shortcuts” dissabled (as it makes me crazy), that was!
Just to give more information, I use KDE desktop with 4 virtual desktops. By default Ctrl + Function keys is a windows manager shortcut for enabling eah virtual desktop.
So yes, I must change such a shortcut in Renoise since I don’t want to enable “Override Window Manager Shortcuts”.
Really thanks a lot.