OK, on Openbox it won't even show the window after terminating aMule, but it will crash instead:
Resolved: 'localhost' -> '127.0.0.1
Connecting to 127.0.0.1:4712
Socket connected to 127.0.0.1:4712
TxCallback signalled, calling EndWrite
RxCallback signalled, calling EndReceive
RxCallback: got 8 bytes, waiting for 0
RxCallback: expecting packet size=14
RxCallback signalled, calling EndReceive
RxCallback: got 14 bytes, waiting for 0
Packet received - call handler
amuleLogicHandler : Authenticated OK
RxCallback signalled, calling EndReceive
Connection terminated on remote side
Connect done
Unhandled Exception: System.NullReferenceException: Object reference not set to an instance of an object
at System.Configuration.CustomizableFileSettingsProvider.LoadPropertyValue (System.Configuration.SettingsPropertyCollection collection, System.Configuration.SettingElement element, Boolean allowOverwrite) [0x0001b] in /home/ise/cvs/extra/devel/mono/src/mono-1.2.6/mcs/class/System/System.Configuration/CustomizableFileSettingsProvider.cs:656
at System.Configuration.CustomizableFileSettingsProvider.LoadProperies (System.Configuration.ExeConfigurationFileMap exeMap, System.Configuration.SettingsPropertyCollection collection, ConfigurationUserLevel level, System.String sectionGroupName, Boolean allowOverwrite) [0x00064] in /home/ise/cvs/extra/devel/mono/src/mono-1.2.6/mcs/class/System/System.Configuration/CustomizableFileSettingsProvider.cs:677
at System.Configuration.CustomizableFileSettingsProvider.GetPropertyValues (System.Configuration.SettingsContext context, System.Configuration.SettingsPropertyCollection collection) [0x00030] in /home/ise/cvs/extra/devel/mono/src/mono-1.2.6/mcs/class/System/System.Configuration/CustomizableFileSettingsProvider.cs:703
at System.Configuration.LocalFileSettingsProvider.GetPropertyValues (System.Configuration.SettingsContext context, System.Configuration.SettingsPropertyCollection properties) [0x00000] in /home/ise/cvs/extra/devel/mono/src/mono-1.2.6/mcs/class/System/System.Configuration/LocalFileSettingsProvider.cs:68
at System.Configuration.ApplicationSettingsBase.CacheValuesByProvider (System.Configuration.SettingsProvider provider) [0x00067] in /home/ise/cvs/extra/devel/mono/src/mono-1.2.6/mcs/class/System/System.Configuration/ApplicationSettingsBase.cs:179
at System.Configuration.ApplicationSettingsBase.GetPropertyValue (System.String propertyName) [0x00042] in /home/ise/cvs/extra/devel/mono/src/mono-1.2.6/mcs/class/System/System.Configuration/ApplicationSettingsBase.cs:201
at System.Configuration.ApplicationSettingsBase.get_Item (System.String propertyName) [0x00000] in /home/ise/cvs/extra/devel/mono/src/mono-1.2.6/mcs/class/System/System.Configuration/ApplicationSettingsBase.cs:209
at amule.net.amuleXferControlSettings.get_FilenameVisible () [0x00000] in /home/johkra/devel/amule-dev.compile/src/remote-gui.net/DownloadControl.cs:43
at amule.net.amuleDownloadStatusList.UpdateColumnIndexes () [0x0000b] in /home/johkra/devel/amule-dev.compile/src/remote-gui.net/DownloadControl.cs:155
at amule.net.amuleDownloadStatusList..ctor () [0x0017b] in /home/johkra/devel/amule-dev.compile/src/remote-gui.net/DownloadControl.cs:216
at (wrapper remoting-invoke-with-check) amule.net.amuleDownloadStatusList:.ctor ()
at amule.net.MainWindow.MainWindow_Load (System.Object sender, System.EventArgs e) [0x0013f] in /home/johkra/devel/amule-dev.compile/src/remote-gui.net/MainWindow.cs:139
at System.Windows.Forms.Form.OnLoad (System.EventArgs e) [0x00022] in /home/ise/cvs/extra/devel/mono/src/mono-1.2.6/mcs/class/Managed.Windows.Forms/System.Windows.Forms/Form.cs:2067
at System.Windows.Forms.Form.OnLoadInternal (System.EventArgs e) [0x00023] in /home/ise/cvs/extra/devel/mono/src/mono-1.2.6/mcs/class/Managed.Windows.Forms/System.Windows.Forms/Form.cs:2883
at System.Windows.Forms.Form.OnCreateControl () [0x00027] in /home/ise/cvs/extra/devel/mono/src/mono-1.2.6/mcs/class/Managed.Windows.Forms/System.Windows.Forms/Form.cs:2017
at System.Windows.Forms.Control.CreateControl () [0x0009e] in /home/ise/cvs/extra/devel/mono/src/mono-1.2.6/mcs/class/Managed.Windows.Forms/System.Windows.Forms/Control.cs:3608
at System.Windows.Forms.Control.WmShowWindow (System.Windows.Forms.Message& m) [0x00036] in /home/ise/cvs/extra/devel/mono/src/mono-1.2.6/mcs/class/Managed.Windows.Forms/System.Windows.Forms/Control.cs:5434
at System.Windows.Forms.Control.WndProc (System.Windows.Forms.Message& m) [0x001dc] in /home/ise/cvs/extra/devel/mono/src/mono-1.2.6/mcs/class/Managed.Windows.Forms/System.Windows.Forms/Control.cs:5067
at System.Windows.Forms.ScrollableControl.WndProc (System.Windows.Forms.Message& m) [0x00000] in /home/ise/cvs/extra/devel/mono/src/mono-1.2.6/mcs/class/Managed.Windows.Forms/System.Windows.Forms/ScrollableControl.cs:717
at System.Windows.Forms.ContainerControl.WndProc (System.Windows.Forms.Message& m) [0x0003d] in /home/ise/cvs/extra/devel/mono/src/mono-1.2.6/mcs/class/Managed.Windows.Forms/System.Windows.Forms/ContainerControl.cs:560
at System.Windows.Forms.Form.WndProc (System.Windows.Forms.Message& m) [0x0017c] in /home/ise/cvs/extra/devel/mono/src/mono-1.2.6/mcs/class/Managed.Windows.Forms/System.Windows.Forms/Form.cs:2483
at System.Windows.Forms.Control+ControlWindowTarget.OnMessage (System.Windows.Forms.Message& m) [0x00000] in /home/ise/cvs/extra/devel/mono/src/mono-1.2.6/mcs/class/Managed.Windows.Forms/System.Windows.Forms/Control.cs:225
at System.Windows.Forms.Control+ControlNativeWindow.WndProc (System.Windows.Forms.Message& m) [0x00000] in /home/ise/cvs/extra/devel/mono/src/mono-1.2.6/mcs/class/Managed.Windows.Forms/System.Windows.Forms/Control.cs:206
at System.Windows.Forms.NativeWindow.WndProc (IntPtr hWnd, Msg msg, IntPtr wParam, IntPtr lParam) [0x0006a] in /home/ise/cvs/extra/devel/mono/src/mono-1.2.6/mcs/class/Managed.Windows.Forms/System.Windows.Forms/NativeWindow.cs:188
at System.Windows.Forms.XplatUIX11.SendMessage (IntPtr hwnd, Msg message, IntPtr wParam, IntPtr lParam) [0x0008d] in /home/ise/cvs/extra/devel/mono/src/mono-1.2.6/mcs/class/Managed.Windows.Forms/System.Windows.Forms/XplatUIX11.cs:4883
at System.Windows.Forms.XplatUIX11.MapWindow (System.Windows.Forms.Hwnd hwnd, WindowType windows) [0x0003c] in /home/ise/cvs/extra/devel/mono/src/mono-1.2.6/mcs/class/Managed.Windows.Forms/System.Windows.Forms/XplatUIX11.cs:1435
at System.Windows.Forms.XplatUIX11.CreateWindow (System.Windows.Forms.CreateParams cp) [0x00569] in /home/ise/cvs/extra/devel/mono/src/mono-1.2.6/mcs/class/Managed.Windows.Forms/System.Windows.Forms/XplatUIX11.cs:2711
at System.Windows.Forms.XplatUI.CreateWindow (System.Windows.Forms.CreateParams cp) [0x00000] in /home/ise/cvs/extra/devel/mono/src/mono-1.2.6/mcs/class/Managed.Windows.Forms/System.Windows.Forms/XplatUI.cs:450
at System.Windows.Forms.NativeWindow.CreateHandle (System.Windows.Forms.CreateParams create_params) [0x0000c] in /home/ise/cvs/extra/devel/mono/src/mono-1.2.6/mcs/class/Managed.Windows.Forms/System.Windows.Forms/NativeWindow.cs:112
at System.Windows.Forms.Control.CreateHandle () [0x0003f] in /home/ise/cvs/extra/devel/mono/src/mono-1.2.6/mcs/class/Managed.Windows.Forms/System.Windows.Forms/Control.cs:4222
at System.Windows.Forms.Form.CreateHandle () [0x00000] in /home/ise/cvs/extra/devel/mono/src/mono-1.2.6/mcs/class/Managed.Windows.Forms/System.Windows.Forms/Form.cs:1910
at System.Windows.Forms.Control.CreateControl () [0x00044] in /home/ise/cvs/extra/devel/mono/src/mono-1.2.6/mcs/class/Managed.Windows.Forms/System.Windows.Forms/Control.cs:3588
at System.Windows.Forms.Control.SetVisibleCore (Boolean value) [0x0003e] in /home/ise/cvs/extra/devel/mono/src/mono-1.2.6/mcs/class/Managed.Windows.Forms/System.Windows.Forms/Control.cs:4770
at System.Windows.Forms.Form.SetVisibleCore (Boolean value) [0x00071] in /home/ise/cvs/extra/devel/mono/src/mono-1.2.6/mcs/class/Managed.Windows.Forms/System.Windows.Forms/Form.cs:2333
at System.Windows.Forms.Control.set_Visible (Boolean value) [0x0000c] in /home/ise/cvs/extra/devel/mono/src/mono-1.2.6/mcs/class/Managed.Windows.Forms/System.Windows.Forms/Control.cs:3260
at (wrapper remoting-invoke-with-check) System.Windows.Forms.Control:set_Visible (bool)
at System.Windows.Forms.Application.RunLoop (Boolean Modal, System.Windows.Forms.ApplicationContext context) [0x00059] in /home/ise/cvs/extra/devel/mono/src/mono-1.2.6/mcs/class/Managed.Windows.Forms/System.Windows.Forms/Application.cs:731
at System.Windows.Forms.Application.Run (System.Windows.Forms.ApplicationContext context) [0x00014] in /home/ise/cvs/extra/devel/mono/src/mono-1.2.6/mcs/class/Managed.Windows.Forms/System.Windows.Forms/Application.cs:630
at System.Windows.Forms.Application.Run (System.Windows.Forms.Form mainForm) [0x00000] in /home/ise/cvs/extra/devel/mono/src/mono-1.2.6/mcs/class/Managed.Windows.Forms/System.Windows.Forms/Application.cs:618
at amule.net.Program.Main () [0x0000b] in /home/johkra/devel/amule-dev.compile/src/remote-gui.net/Program.cs:41
Edit: OK, now it crashes on xmonad, too. Weird.
But please have a look at the tab order in the login dialog. Western users expect a left-to-right, top-to-down order, whilst you have top-to-down, left-to-right order.