Shortcuts for "Send to Left" and "Send to Right" not working in "Differences Viewer"

I have standard keyboard shortucts set for "Send to Left" and "Send to Right" — Ctrl+1 and Ctrl+2 respectively. However, in "Differences Viewer", when I jump to the specific difference (there's chevron button allowing to copy change from left <read only file> to right <local file>) and press Ctrl+2 nothing happens. I also see no effect when jumping to specific change without chevron button (like deletion) and pressing Ctrl+2.

Any ideas how to copy changes using keyboard shortucts?

Btw, Ctrl+Z (undo) does not work in "Differences Viewer", either.

PyCharm 3.0.1