Keyboard shortcuts

Hi,
I don't understand why sometimes (in some projects) the stated keyboard shortcuts don't work.

For example, DELETE FWD button.

If I have 3 clips consecutive in a timeline, 1 - 2 - 3 (clip 2 inthe middle) and I delete the clip 2 with DELETE FWD key, the clip3 snaps back to be togheter with the the clip 1. If I delete with the DELETE BACK key, there will be a gap between clip 1 and clip 2.

This is the normal situation, right. But sometimes, is the DELETE FWD key which leaves the gap and the DEL BACK key by itself don't erase anything, unless I press Shift+Delete Back, to erase the clip 2 without gaps.

Other cases: Shift+Z doesn't work for zoom, Comand+Z does not make the UNDO, so I have to go to Menu>Edit>Undo... wasting time. And the Preferences are set up accordingly. What could be wrong?

Possibly your keyboard is sticky? Those things all work fine here. Maybe try a newer keyboard.