widget framework error

Hi Guys! I got the following Server Error, when I played around with the widgets: "InvalidArgumentException: Template public:pAGE_CONTAINER error: No widget defined with a widget_key of xp_ucd_menu_list src/XF/SubContainer/Widget.php:80" What did I do wrong? Is there a way to fix this...

Widget Framework 2.6.3 Beta 5 needs fixes for a few remaining issues: https://xfrocks.com/widget-framework/threads/bug-xfmg-media-renderer-does-keeps-loading.462/ https://xfrocks.com/widget-framework/threads/the-server-responded-with-an-error-the-error-message-is-in-the-javascript-console.473/...

My server error is throwing several similar errors every minute related to a plugin. Server Error Log Error Info ErrorException: Undefined variable: forum - library/WidgetFramework/WidgetRenderer.php(498) : runtime-created function:1 Generated By: Unknown Account, 5 minutes ago Stack Trace #0...