Maybe show residential window titles for each desktop in the tooltip? Alternatively or additionally, can the applet show a little screenshot of each desktop as thumbnailing in the tooltip?
Workspace switcher widget is handled by Gnome's libwnck.
Well, there's also some conflict between compiz as the window manager and the little previews inside the plugin's workspace buttons. I remember asked about that issue somewhere, maybe on the mailing list, but not sure any more. Using PCLinuxOS Phoenix here. compiz-0.8.4-3pclos2010 xfce4-panel-4.9.0-1pclos2012
Blocking is only for serious crashes and loosing data.
I see that compiz seems to minimize all windows not pinned to the current desktop, they flip away when another workspace is selected from the panel plugin bar. Can this behaviour to minimize invisible windows be deactived? I know, this question should better go to compiz support.
Downstream tries some fixture. https://bugzilla.redhat.com/show_bug.cgi?id=960661