The testbed is rather limited but it helps you getting a basic idea of how to define a global hotkey.
A hotkey is a string in the form of <key>+<key>+..
<key> values: a - z / A - Z, 0 - 9 SPACE, BACKSPACE, TAB, RETURN, CAPSLOCK, PLUS, MINUS, COMMA, PERIOD, COLON, SLASH, GRAVE, LBOXBRACKET, RBOXBRACKET, BACKSLASH, QUOTE, PRINT, SCROLLLOCK, PAUSE, PAGEUP, PAGEDOWN, END, HOME, INSERT, DELETE, LEFT, UP, RIGHT, DOWN, NUM0 - NUM9, NUMADD, NUMSUB, NUMDIV, NUMMUL, NUMDEC, ESC, F1 - F11
<key> on X11: XStringToKeysym() is used.
While on Windows multiple keys are allowed X11 and OS X only allow a single key to be used as hotkey. e.g. <modifierlist>+R+E works on Windows only.
<key> for modifier keys:
- Windows: LCONTROL, RCONTROL, LSHIFT, RSHIFT, LALT, RALT, WIN, APPS
- OS X: CONTROL, SHIFT, COMMAND, OPTION
- X11: CONTROL, SHIFT, MOD1 - MOD5