sequence -The key sequence for this binding. This key sequence should consist of one or more key strokes. Key strokes are separated by spaces. Key strokes consist of one or more keys held down at the same time. This should be zero or more modifier keys, and one other key. The keys are separated by the + character.
The recognized modifiers keys are M1, M2, M3, M4, ALT, COMMAND, CTRL, and SHIFT. The "M" modifier keys are a platform-independent way of representing keys, and these are generally preferred. M1 is the COMMAND key on MacOS X, and the CTRL key on most other platforms. M2 is the SHIFT key. M3 is the Option key on MacOS X, and the ALT key on most other platforms. M4 is the CTRL key on MacOS X, and is undefined on other platforms.
The actual key is generally specified simply as the ASCII character, in uppercase. So, for example F or , are examples of such keys. However, there are some special keys; keys that have no printable ASCII representation. The following is a list of the current special keys: ARROW_DOWN, ARROW_LEFT, ARROW_RIGHT, ARROW_UP, BREAK, BS, CAPS_LOCK, CR, DEL, END, ESC, F1, F2, F3, F4, F5, F6, F7, F8, F9, F10, F11, F12, F13, F14, F15, FF, HOME, INSERT, LF, NUL, NUM_LOCK, NUMPAD_0, NUMPAD_1, NUMPAD_2, NUMPAD_3, NUMPAD_4, NUMPAD_5, NUMPAD_6, NUMPAD_7, NUMPAD_8, NUMPAD_9, NUMPAD_ADD, NUMPAD_DECIMAL, NUMPAD_DIVIDE, NUMPAD_ENTER, NUMPAD_EQUAL, NUMPAD_MULTIPLY, NUMPAD_SUBTRACT, PAGE_UP, PAGE_DOWN, PAUSE, PRINT_SCREEN, SCROLL_LOCK, SPACE, TAB and VT.
We also understand some alternative names for some common special keys. For example, we accept both ESC and ESCAPE, and CR, ENTER and RETURN are all the same.
It is also strongly recommended that you keep the key sequences short. One or two is the most you should need. Use contexts to give key sequences different meanings in different parts of your application. At the very most, you should not use any key sequence that contains more than four key strokes.