Ctrl-C does not work in diff viewer

Still on v1.4.3.5-59-gdda8093, Ctrl-C\* in the diff viewer copies the file name rather than the selected text, which bites me all the time forcing me to right-click and click "copy" to copy an identifier from the diff to paste it into the commit message.

*On OS X, that's Cmd-C, but I assume that's a detail.
