How to change the keyboard shortcut for Firefox's context menu?

Question

I am trying to change the keyboard shortcut for showing the context menu in Firefox (the equivalent of pressing Shift-F10 on Linux or Windows or Control-Space on OS X). It seems like this shortcut is handled at a different level from normal keyboard shortcuts (it doesn't show up in the Keyconfig extension that allows remapping of most keyboard shortcuts).

I have tried creating key and mouse events to trigger the context menu (using the following code that is mapped to a shortcut with Keyconfig) but they haven't worked so far. I haven't been able to track down where in the source code Firefox handles the keyboard shortcut for the context menu or if there is a single function that I could call to show it.

Mouse event:

var focused = document.commandDispatcher.focusedElement;
if(!focused) focused = document.commandDispatcher.focusedWindow.document.activeElement;
var evt = document.createEvent("MouseEvents");
evt.initMouseEvent("click", true, true, window,
0, 0, 0, 0, 0, false, false, false, false, 2, null);
focused.dispatchEvent(evt);

Key event:

var focused = document.commandDispatcher.focusedElement;
if(!focused) focused = document.commandDispatcher.focusedWindow.document.activeElement;
var evt = document.createEvent("KeyboardEvent");
evt.initKeyEvent("keypress", true, true, null, false, false, true, false, 0x79, 0);
focused.dispatchEvent(evt);

score 1 · Accepted Answer · edited May 23 '17 at 12:41

I found that this same question had been asked previously on MozillaZine here. That solution puts the context menu in the top left corner of the screen. I tried using the solution given to this other question about getting DOM screen positions to produce the code below which places the context menu closer to the active element, but it is still buggy (sometimes the menu is a bit off from the element):

var target = (document.commandDispatcher.focusedElement || document.commandDispatcher.focusedWindow.document.documentElement);

var screenX=0;
var screenY=0;
if ("boxObject" in target) {
  screenX=target.boxObject.x;
  screenY=target.boxObject.y;
} else {
  var box;
  try {
    box = elem.getBoundingClientRect();
  } catch(e) {}

  // Make sure we're not dealing with a disconnected DOM node
  if (box) {

    var body = document.body,
      clientTop = document.documentElement.clientTop || body.clientTop || 0,
      clientLeft = document.documentElement.clientLeft || body.clientLeft || 0,
      scrollTop = window.pageYOffset || body.scrollTop,
      scrollLeft = window.pageXOffset || body.scrollLeft,
      top = box.top + scrollTop - clientTop,
      left = box.left + scrollLeft - clientLeft;
  }

  screenX=target.offsetLeft;
  screenY=target.offsetTop;
}

var e = document.createEvent("MouseEvents");
e.initMouseEvent("contextmenu", true, false, null, 0, screenX, screenY, 0, 0, false, false, false, false, 0, null);
target.dispatchEvent(e);

How to change the keyboard shortcut for Firefox's context menu?

1 Answers1