The panels would not appear anymore. I am now panel less. I could not access it in the systems manager. Clicking the panels button would not bring it up. I don't know what brought the problem up but it happens after I used the package manager. Also the same thing about the "upper panel not hiding bug" that I post long ago. Now is just more severe.
Is this a duplicate of http://bugzilla.xfce.org/show_bug.cgi?id=2130 ? If so, it still needs a backtrace to help find the issue.
My experience, I hope that help fix this bug: In the bottom panel preferences, if I choose "always group tasks" the panel crash (flickering then disappeared) frequently with floating point exception. But if I choose "never group task" (in .config/xfce4/panel/tasklist-2.rc grouping=0) the panels seems stable. xubuntu xfce4-panel-4.6.3-1ubuntu2
aknowledged. i also have that problem with xfce4-panel (grouping tasks). here is the gdb-output for that floating point exception: Program received signal SIGFPE, Arithmetic exception. 0x0000003281408836 in xfce_itembar_size_allocate (widget=0x6d9d00, allocation=0x7fffffffd0b0) at xfce-itembar.c:519 519 expand_size = MAX (itembar_expandable * size / itembar_expandreq, 0);
Should be fixed in >= 4.7 panel.