Attributes [Browsable(false)] and [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)] were added to properties that couldn't be used in a form editor and throw warnings during serialization.

Related:
http://www.codeproject.com/Questions/128351/Code-generation-for-property-yyy-failed
https://stackoverflow.com/questions/9789066/usercontrol-collection-not-marked-as-serializable/11200773#11200773
PostBuildEvent with release DLL output