Plugins are registered with PluginMainThreadScheduler when they are started, but in Qt port, they are not unregistered when they are stopped. This can lead to an assertion failure in PluginMainThreadScheduler::registerPlugin if the same address is reused for a new NPP instance.
Created attachment 30200 [details] Add call to unregister the plugin when it is stopped
Comment on attachment 30200 [details] Add call to unregister the plugin when it is stopped Same fix is needed for Gtk+ :)
Windows is doing it below the "Clear Window" but I assume it is okay, landed in r43550.