Comment by Sinatr on Splitting a winforms form into multiple partials confuses the VS designer

I dislike the idea of splitting form. The big part of winforms designer rely on autogenerated code, therefore partial, not because it expect you to split it even further. The idea with attribute, which should only affect a part of class is even more weird. It just doesn't work this way. You may want to consider composition instead of inheritance, ideally separating business logic from view completely, but multiple small isolated UserControls is an intended way.