Basically you would be swapping the two keys. One possible way to fix this is that because remapping Command to Control eliminates access to Control key shortcuts, you could also remap Control to Command so that you can regain access to shortcuts that need the Control key like Control-U. That's my theory on why Control-U stopped working for you: You told the Command-U feature (underline text) to replace the former Control-U feature (edit active cell). Therefore, Command-U (underline text) is now Control-U, and whatever was Control-U before (edit active cell) is disabled since a shortcut can only mean one thing at a time. Because in Mac Excel, Command-U (apply underline formatting) and Control-U (edit selected cell) are two different features, so if you remapped Command to Control at the system level, Excel now behaves such that all Command-modifier shortcuts are now Control. On Control-U: I am wondering if this no longer works on your Mac because you remapped Command to Control. So I'm starting to think that there is a configuration problem somewhere on your Mac. I also pressed F2 and I was again able to edit it. I pressed Control-U and I was able to edit it. I opened up Mac Excel 2011 and selected a cell. I have just done a little experimenting and I think I have some idea of why you're having a problem.
