Copying cells

Hi, Sorry to post the same topic, but I seem to be stuck with this: in my exposure sheet, copy/paste cells within an element is recognized as copy /paste new object even if use the simple paste (cmd/v) shortcut. However, on the timeline sheet, simple copy/paste works! I usually work frame by frame on exposure sheet, so I need to fix this. My TBS 6 used to work smoothly before I upgraded my Mac OSX! Please Help!

Are you using 10.7 or 10.8?
Check the shortcut if there is any changes.
You can try right click (or Control + click) on the cell in xsheet to have the list of command and select from there if selecting option would work. Then check the shortcut displaying in the menu when you do the right click if it is written as Coomand +V instead of Command+Shift+v which is creating it as new object. You can also check the general key setting on Mac if it causes the issue