I'm not sure my original posting took or registered for notice so I'm doing it again.
I wish to make my Panel bar totally transparent so it's not visible at all in auto-hide mode. In MATE, I adjusted Panel Properties' style transparent/opaque box and it almost fully does the job, but the icon frames of apps like Workplace Switcher and Launcher Properties don't change transparent on the Panel bar and stand out while the rest of the panel bar is invisible. Under XFCE and its Panel prefs, setting Opacity at 100% Enter and 0% Leave makes the entire panel bar transparent, Launcher and Workspace Switcher included. Is there any remedy to do the same total effect under MATE?
Jim in NYC