That's interesting Scribbler. I'm currently using Synergy with a whole set of hotkeys for my second box, and I haven't run into any problems.

Based on what you're showing, are you making sure that you are defining which screen you want the keyboard input to go? Here's how one of my hotkey bindings looks in the Synergy GUI:

Hotkey: keystroke(Control+1)
Action: A keystroke(1, screen2)

For those unfamiliar with Synergy (which is probably not many on here, heh), when I press CTRL-1 (on either box) a "1" is sent to my second box.

I just tested using the F-keys for bindings, and it worked fine. One of the easiest ways I test bindings is to open notepad on the second box (if your binding is a typeable character that is) and see what happens.

If you don't have any luck, let me know!