Comment 39 for bug 50839

(In reply to comment #10)
> is the linux equivalent of bug 483136 - a regression of bug 333166 with
> regression range per bug 407500 comment 9?

Although this isn't a regression from bug 333166, it's likely the same issues: 1) a scroll event sent to the plugin does not get propagated to the browser.
2) scroll events are sent to the plugin even when scrolling begins with
   the mouse outside the plugin.

If the scrolling begins with the mouse outside the plugin, one thing that maybe could be done is to grab the pointer for the duration of scrolling, sending events to the window where scrolling started.

If the scrolling begins with the mouse over the plugin, then the user may be trying to scroll something in the plugin, so the plugin needs to receive the scroll event. If the plugin replies saying that it has consumed the event, then there is not much Gecko can do but assume that the plugin acted on the scroll event.