Designer freezes on complex form when Document Outline is open

I have a complex form with multiple tabs, panels on each tab, different panels in each tab, etc.

My computer is very modern but I’m experiencing a lot of lag and slowdowns, freezes when making designer modifications while the Document Outline panel is open in Visual Studio.  Closing Document Outline, the designer becomes much more responsive.

I’m not sure I’d design such a complex form in the future, but for now this is what I work with.