1,224 votesAnonymous commented
On one side you say you like the WinForms API since it s so easy to use, on the other you want to implement stuff which will break your old workflow to be implemented realistically. Trying to make the Win.Forms library something it isn't is silly. This request is very narrow-minded.
Open sourcing old parts of the .NET Framework is indeed a much more general request. But that will not happen due to licensing. Nobody stops you from wrapping the old WinAPI UI stuff with all its issues and relicts and compatibility issues by yourself and do something WPF already has (including utilizing modern UI technology) - WinForms is a very thin layer on top of that. If you really want all your features to happen, you finish reimplementing them earlier than waiting for MS to put old .NET Framework parts under a permissive open source license.