JakubMisek Just a heads up, this one is going back to the Development Team tomorrow.
I'm not sure if you are aware of the big shit storm that has been brewing over the new collapse symbols they introduced in v.17.9. Here it is if you missed it:
"Outlining in 17.9 uses ugly "v" for collapse/expand instead of the previous "+" with a box. We have no option to restore things to how they should be."
https://developercommunity.visualstudio.com/t/Outlining-in-179-uses-ugly-v-for-coll/10584634#T-ND10677516
Once of the people got tired of waiting on Microsoft and their complete disregard for the concerns of the community and coded a plugin that is available in the Visual Studio Store yesterday. I downloaded it today and installed it, and guess what?
95% of the problem has disappeared!
When I close VS down and reopen it later, or load another project and then reload the current project, the expanded regions are still expanded and the closed regions are still closed.
This tells me that the problem is with their new and "wonderful" implementation for collapsing regions.
Of course, with how the MS development team completely ignored the above problem in the first place, I am not hoping form much, but it's worth a shot.
I just wanted to update this and will keep you posted.