WebBrowserComponent mouse focus/resizing issue on 10.11

I've got an issue with the WebBrowserComponent on 10.11, which isn't a problem on 10.9. It seems that it steals mouse focus as soon as the mouse enters the component (even if dragging on another component). This means that when I am trying to resize it using StretchableLayout components, I can't make the WebBrowserComponent's area smaller, without going exteremly slowly and staying over the StretchableLayoutResizerBar.

hopefully this video makes the issue a little clearer:


I remember Jules was talking a lot recently about mouse handling on OSX and the problems associated with it... so he's definitely the expert here :-) Unfortunately I believe we'll have to wait until Jules is back from NAMM for a solution. Please be patient!

<groan> Jeez, thanks a lot, Apple..

OK, thanks for the heads-up, we'll have a look at this as soon as poss. Probably going to be a nasty one to solve though, I can't make any promises..

any ideas if this can be fixed?