missing offsetX and offsetY in firefox

[machnikv@…]

In firefox are offsetX and offsetY in events undefined.

Bugfix: Paste into mouseHooks -> filter function (line 3384) befor 'return event;' this to lines:

event.offsetX = event.offsetX

event.clientX - jQuery(event.target).position().left;

event.offsetY = event.offsetY

event.clientY - jQuery(event.target).position().top;

[anonymous]

#edit

event.offsetX = event.offsetX || event.clientX - jQuery(event.target).position().left;
event.offsetY = event.offsetY || event.clientY - jQuery(event.target).position().top;

[dmethvin]

Duplicate of #8523.