Background: When using a short vertical panel on the left hand side of the screen, full-screen video playback was spoiled by two thin horizontal lines right across the screen, corresponding to the positions of the top and bottom ends of the panel. This appeared to be related to the 3-pixel panel hint bar which never disappears, even when the panel is hidden. Following Rockhopper's suggestion here, http://rockhopper.dk/linux/software/xfce/completely-hide-xfces-panels/ I enabled the compositor and set Panel->Appearance->Opacity->Leave to zero. This worked and fixed the video problem, but on next logon, the thin panel hint bars were back. The settings were not forgotten(!) but they weren't being followed. Bug: On each login, the compositor has to be switched off and back on again to honour the panel opacity setting. xfwm4 4.8.1-1 Xubuntu Natty plus all updates to date PCI bridge: Intel Corporation 82850 850 (Tehama) Chipset AGP Bridge (rev 02) Display controller: ATI Technologies Inc RV350 AS [Radeon 9550]
Just to note, on login the panel opacity is being set by Window_Manager_Tweaks->Compositor->Opacity_of_popup_windows. This is unexpected. After disabling and re-enabling the compositor, it is set by Panel->Appearance->Opacity->Leave as mentioned above. Once the compositor has been restarted there are a couple of minor disadvantages:- 1) The panels are slower to appear. First the 3-pixel panel hint is drawn and then there's a delay before the panel itself is drawn. It's marginal but gives the interface a "sluggish" feel. 2) When editing the panel, e.g. moving a launcher to a different position, the panel stays completely hidden and cannot be shown even by moving the mouse to the edge of the screen. So it becomes necessary to adjust the "Leave" opacity before editing the panel. Perhaps the panel opacity could be forced to the "Enter" value during editing. Cheers.
Testing Xubuntu Oneiric now and this bug seems to be fixed in packages xfwm4 4.8.1-3 xfce4-panel 4.8.5-1ubuntu1 The two minor issues of the previous post remain but the compositor bug is gone. Thanks.