Detecting mouse clicks anywhere on screen

[Kerrick Staley <mail kerrickstaley com>]

Hi,
I'm trying to write an extension that will toggle the overview
whenever mouse button 9 is clicked, but I can't figure out how to
detect clicks from arbitrary locations on the screen.

global.stage's button-press-event will fire when you click the mouse
anywhere within the overview, but when the overview is hidden, only
clicks on the panel will cause button-press-event to fire.

My current code follows:

const Main = imports.ui.main;
const Lang = imports.lang;

function init() { }

function enable() {
    global.stage.connect('button-press-event', Lang.bind(this,
function(actor, event) {
        if (event.get_button() == 9)
            this._toggleOverview();
    }));
}

function disable() { }

function _toggleOverview() {
    if (Main.overview.visible)
        Main.overview.hide();
    else
        Main.overview.show();
}

- Kerrick