I set the kwin windows operations menu to be shortcut of alt-space. It let me, I hit ok when it told me it was taking it from krunner. I hit apply and tried it, it did nothing. I went back to keyboard control panel and tried again on a whim, and it had not applied.... I added it, and hit apply, and now it works. I can alt-space c all I want now... but that was a funny bug.
Hi - merging this in with an existing bug report for the same core issue. Thanks! *** This bug has been marked as a duplicate of bug 471370 ***