Hi @Euris,
Welcome to Microsoft Q&A!
You can close all running VS instances and try to delete the hidden .vs, bin and obj folders in the project folder.
Then, reload the project and check it again.
As it occurs in a specific form, I suppose it is not a VS issue. Maybe you can back up the project and consider creating a new form in the project, which may help to narrow down this issue.
Besides, you can also try to repair your VS2019 with Visual Studio installer.
Sincerely,
Anna
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