VS2022, VS2026 winforms designer for .net framework wants to load System.Runtime.dll v. 10.0.0.0

[AdmiralSnyder]

sorry, there wasn't a issue template for the .net framework winforms designer, so i create this blank one.
here's a screenshot of the stacktrace.

here's a link to the devcom issue we created yesterday:_
https://developercommunity.visualstudio.com/t/winforms-net48-designer-fails-to-load-S/11001203?port=1026&fsid=38f24fd5-33b2-4177-974d-62cb0c6993f4

We suspect it's because we have properties on the base form (that gets instanciated) where the types are coming from netstandard 2.0 assemblies or ones that are multitargeting both net10.0 and net48,
We think that, because in one specific case, the error goes away if we uncomment a certain property. sadly, that doesn't work for most of our forms. (see the linked devcom issues for details)

Is there a way to debug into the FilterApplyMethodsBase call, by any chance?

i remember, back in the day, you could attach a second VS and sometimes make progress there. why isn't that possible, here?

[elachlan]

@Shyam-Gupta might be able to help?

[AdmiralSnyder]

Small update: the immediate pressure for us is lowered a little bit, since we figured out a workaround (switching the order of the entry in the .csproj so that netfx is first)

BUT this problem was introduced before we were multitargeting, so it must be somewhere else in the winforms designer - and it can break again, anytime, i suppose.

SO this still should be fixed. I provided a reproduction in the devcom ticket (which took me an entire working day to build), so you have all means to do that, now.