The designer was called Blend - it was started by a dev that, among many other things :), created the designer for WinForms. And the hacks they had to make in W

The designer was called Blend - it was started by a dev that, among many other things :), created the designer for WinForms. And the hacks they had to make in WPF to support any VisualStudio designer (WPF had to detect if it was running in designer mode and do things differently https://learn.microsoft.com/en-us/dotnet/api/system.componentmodel.designerproperties.getisindesignmode https://learn.microsoft.com/en-us/dotnet/api/system.componen...)