I have been using WinMerge for many years. I just saw CodeCompare today on Wikipedia (the file comparison tools entry), so I downloaded it and had a try.
Some suggestions below.
1) When the text cursor (caret) is on the left file and user presses [Ctrl+Alt+Right] to do CopyToRight, please do NOT let the caret jump to the right file. This is because : when user is doing merge, left file is to be edited and right file may usually be a reference (maybe read-only). And this behavior introduces another problem as stated in issue (2) below.
2) When the caret is on the left file and user wants to merge using the line on the right file, CodeCompare does not handle [Ctrl+Alt+Left] to synchronize with the line content of the right file. This is quite inconvenient.