I have "Automatically hide the panel: Intelligently" and in Window Manager Tweaks I have checked "Hide title of windows when maximized" to get a fullscreen effect when programs a maximized without the need to do ALT + SPACE and then choose fullscreen. The problem is that when I drag my mouse up to the edge of the screen and the panel 0 appears it disappears again when I for example click "Window Buttons". I am using xfce4-panel 4.12.0 and xfce4-whiskermenu-plugin 1.5.0. I have a video which demonstrates it all and what parts on panel 0 that are affected by this behaviour. I notice that when it comes to programs it is mostly or only maximized programs that make panel 0 disappear but also for example Power Manager Applet and Hexchats system tray icon. (Theora/mkv, 02min09sec, 16MB) http://speedy.sh/qKkaJ/testrecord2.mkv
The video doesn't exist anymore. Plus when you click a program it comes to the front and will overlay the panel, so intellihide will correctly hide it.