Comment 19 for bug 1635577

OK, after all I think it is an issue in unity-panel-service.

ownCloud does strange things: it unregisters and re-registers its tray icon periodically. This results in creating new indicator items every time. The new items are added to the menu by gtk_menu_shell_append call in panel_service_show_entry_common function. However, then the old indicator items get removed, the menu items are not removed (there is no corresponding gtk_container_remove call), they are just hidden by unsetting their entry2geometry hashes.

I hope Unity developers will be able to look at this more closely, and I will backport the upstream fix for ownCloud for the time being.