When telling an application to be both
always on visible workspaceand
always on top
this works, BUT, when switching workspaces, said application is not only
always on top but also "always in focus by default" in all workspaces.
In other words, it ( Compiz ? Unity ? ) does not remember being "blurred" (ie, having lost focus to some other application) in a given workspace, but rather reliably (and reproducibly) forgets all about it, as soon as switching to another workspace and then switching back again.
This is not sth I'd want to use every day, but right now I was wanting to have a long-ish Video in VLC running as a "Picture-in-Picture"-type thing which I'd pause and ignore and then run a bit more etc, whilst frequently switching workspaces; basically keeping said application in the background (somewhere on my large screen), but still visible, ie, "on top".