[quote user="Maury"]I just switch my build to a custom "Design" configuration which defines DESIGN and created this custom class[/quote]
I agree it's quite elegant solution. I use the same approach (to define custom Configurations) to control usage of analyzers. They provide great feedback about code quality, but substantially increase compilation time: Now my new projects contain usually Debug and Debug (analyzers), where Debug is configured to use standard rules (I guess they are Microsoft Managed Recommended Rules) and Debug (analyzers) with several different analyzers applied.
So I can imagine to use Debug and Release Configurations where Adapter is inherited and the code compiled correctly and e.g. Debug (form design) where Form class is used and WinForm designer can be used.
With regards,
Jan