I also get this Error when i try todo something in the Admin Panel
Error: Call to a member function contents() on null (0)
#0 /home/luthenne/public_html/community/applications/core/modules/admin/customization/icons.php(140): IPS\core\modules\admin\customization\_icons::processApplicationIcon(Array, Array, Array)
#1 /home/luthenne/public_html/community/system/Dispatcher/Controller.php(101): IPS\core\modules\admin\customization\_icons->manage()
#2 /home/luthenne/public_html/community/applications/core/modules/admin/customization/icons.php(38): IPS\Dispatcher\_Controller->execute()
#3 /home/luthenne/public_html/community/system/Dispatcher/Dispatcher.php(153): IPS\core\modules\admin\customization\_icons->execute()
#4 /home/luthenne/public_html/community/admin/index.php(13): IPS\_Dispatcher->run()
#5 {main}