>>> My Info: Win7_64, Nightly 49, 32bit, ID 20160526082509 STR_1: 1. Switch Firefox window to normal (not maximized) mode 2. Open url [1] or url [2] or url [3] 3. Hover mouse over the map on the page, hold left mouse button 4. Move mouse outside of the window 5. Move mouse over any iframe on the page AR: In Step 4 map follows mouse pointer. In Step 5 map stays still ER: In Step 5 map should also follow mouse pointer Note: Result of Step 4 proves that mousemove event fires even OUTSIDE THE WINDOW. > [1] http://msk.rusavtobus.ru/ > [2] http://wikiroutes.info/msk > [3] data:text/html,<script>onmousemove=function(e){D.innerHTML = e.screenX+" - "+e.screenY}</script><div id="D"></div><iframe></iframe>

Per discussion with Stone, it seems something goes wrong with event target determination.

Whatever the discussion was about, please note that bug 185919 "beats" this bug, but this one has additional conditions (left mouse button being pressed). And it doesn't look like there was a strong decision about bug 185919... I think it is the main problem here. Also, Google Chrome browser does the same thing as Firefox here.

Can't be reproduced the problem with url [1] and [2] in the bug description on Chrome. Only url [3] can be reproduced on Chrome. Also observed that Chrome fires mousemove events to the listeners of the document when the mouse left button is hold (on the map) and moved on the iframe of url [2].