Firstly, thank you to the developers and surrounding community of Xfce for producing what has proven for me to be the most exceptional desktop environment in existence. I have been using Xfce full-time for over 3 years. The blend of functionality, configurability and speed has put me in a situation where no other DE comes even close to being good enough for my purposes.

I run ArchLinux, however i'm something of an unusual case in that ArchLinux is a rolling-release distro but rather than rolling with it I make a snapshot of the repo every 9-12 months and run off that. The reason I do this is that I really like Arch for a number of reasons, but i'm not interested in regularly risking the introduction of new problems/bugs that can come with updating software versions on a (potentially) daily basis. I make my snapshot, address any issues i find myself, then can feel secure that my setup will continue working day in, day out.

In August I made a new snapshot of the Arch repo and today have finally gotten around to installing from that.

The Problem:
I have 2 screens, they are configured using "Separate X screens" (that's what the configuration tool that comes with nVidia's binary driver calls it, I believe it's an accurate term), not Xinerama or 'TwinView' or anything like that. Separate X Screens means I cannot drag applications from one screen to another, but it eliminates most all issues with fullscreen applications being able to stay properly confined to one screen.

Part of my recent update included going from Xfce 4.8 to Xfce 4.10. Since updating, I now experience an issue with fullscreen media playback. I've tested with both VLC and (s)mplayer; If I have an application open my left screen and I start playing media on that screen, fullscreen the media, and then move the mouse cursor back over to the right screen, the second i focus an application on the right screen the open application on the left screen shifts to be on top of the fullscreen-playing media.

If I set the media player to be 'Always on Top', this does prevent the applications behind the fullscreen media from moving to the front, but that's far from optimal and not an appropriate solution.

It's pretty odd. If no application is running on the right screen, it's fine, it's only once I focus an application there that the applications on the left screen jump in front of the playing media.

When first testing with VLC I thought it was probably a VLC problem, but then when I saw the same behaviour with (s)mplayer, I figured XFWM was the issue. I've tried toggling any of Xfce's settings I thought could be at all related, but to no avail. (Tried all seemingly related settings in 'Windows Manager' and 'Window Manager Tweaks' settings dialogues)

The package version of XFWM i'm running is 4.10.0-2, which is still the latest in Arch's repos to this day.

Any suggestions to resolve this would be appreciated.
I tried searching the forums first but found no similar posts with the search terms i used. Sorry if i missed something.