This seemed to be caused by having multiple Window List. I had an extra one squeezed down so that it was no longer visible. When I removed second one, the visible WIndow List worked as expected
-- You received this bug notification because you are a member of Desktop Packages, which is subscribed to gnome-panel in Ubuntu. https://bugs.launchpad.net/bugs/869535 Title: A window dragged off to another Xinerama display disappears from Window List applet Status in “gnome-panel” package in Ubuntu: New Bug description: I have nVidia, Ubuntu Classic/Gnome and 3 displays BUG: Today I noticed in gnome-panel 1:2.32.1-0ubuntu6.5 that a window that is dragged off my center screen disappears from the Window List applet of that screen. The Window List applet supposedly lists all windows as buttons so that you can quickly switch in between Expected: All windows on all Xinerama display's to appear in Window List ProblemType: Bug DistroRelease: Ubuntu 11.04 Package: gnome-panel 1:2.32.1-0ubuntu6.5 ProcVersionSignature: Ubuntu 2.6.38-11.50-generic 2.6.38.8 Uname: Linux 2.6.38-11-generic x86_64 NonfreeKernelModules: nvidia Architecture: amd64 Date: Thu Oct 6 14:35:32 2011 GConfNonDefault: /apps/panel/general/applet_id_list=[applet_10,applet_7,applet_9,applet_8,applet_4,fast_user_switch_screen0,indicator_applet_screen0,notification_area_screen0,clock_screen0,mixer_screen0,applet_1,applet_2,applet_5,applet_3,applet_6,applet_11,applet_12,applet_13,applet_14,applet_15,applet_16,applet_17,applet_19,applet_18,applet_20] /apps/panel/general/object_id_list=[object_5,object_0,object_3,browser_launcher_screen0,object_1,object_2,object_6,object_7,object_9,object_10,object_8,object_12,object_4,object_16,object_20,object_22,object_21,object_23,object_24,object_25,object_27,object_28,object_18,object_17,object_26,object_19,object_13,object_29,object_30,object_32,object_33,object_34,object_37,object_14,object_31,object_11,object_15,object_35] /apps/panel/general/show_program_list=true /apps/panel/general/toplevel_id_list=[top_panel_screen0,panel_0,panel_1] ProcEnviron: LANGUAGE=en_US:en PATH=(custom, user) LANG=en_US.UTF-8 SHELL=/bin/bash SourcePackage: gnome-panel UpgradeStatus: Upgraded to natty on 2011-04-23 (166 days ago) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-panel/+bug/869535/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp

