I worked with 'deselect' set to Alt+D for weeks. Rarely I got the message that the shortcut is ambiguous. Now it happens every time. I have no idea what it could collide with. It also doesn't seem to have anything to do with selected tool. I work with Krita 2.9.11 on Windows 10.

I've already changed my shortcuts many, many times because of ambiguousity and perspective of doing it again drives me crazy, to be honest.

I don't even know if it's a bug or some feature I don't know about. Can anyone explain me what's happening?

This was a deep-lying problem with the shortcuts that has been fixed in 3.0(basically, it recognised shortcuts that would only apply on Linux)

Excuse the off topic intromission, but is Calligra 3.0 ready finally? In Calligra's site they still show the 2.9 branch as the latest.

I wouldn't know, Krita isn't part of Calligra any more. We have our own Repository now.(We're still a KDE project, of course, so there's still fluidity in sharing code and contributions)

Oh, so finally got separated from Calligra... Nice, I think many people thought that it was weird to include a drawing app in an office suite.
As you said, I see now that my distro has it available to install as a stand alone program. I'll install it now, as I use Krita a lot for photo retouching, even if many years ago it got focused on drawing, but still is a great photo editor, and the integraton of G'mic contributed a lot to it. Wise decision.

Thanks.