In visual studio we have MDriven code that makes up the designtime experience. This is the model and the OCL-Editor and the like.

One of the older things of MDriven are the WindowsForms Handles; ExpressionHandle, ReferenceHandle and CursorHandle to mention a few.

These handles connects to the DesignTime code for Visual Studio that we find in Eco.Handles.Design.

We run into a problem when Visual Studio compiles your code and find MDriven assemblies in it - specifically the Eco.Handles.dll. Visual studio will copy that Eco.Handles.dll from your project and put it in a directory like this:

C:\Users\hans\AppData\Local\Microsoft\VisualStudio\17.0_d364b061Exp\ProjectAssemblies\cobgw1bv.p2l01\Eco.Handles.dll

Now whenever your WindowsForms designer code is de-serialized in design time (executed to actually assign properties) - Visual Studio will first look in ProjectAssemblies - and find a copy of Eco.Handles.dll there - it will load this even though we have one loaded from where we installed the MDriven-Extension:

C:\USERS\HANS\APPDATA\LOCAL\MICROSOFT\VISUALSTUDIO\17.0_D364B061EXP\EXTENSIONS\MDRIVEN AB\MDRIVENFRAMEWORK\7.0.0.14859\Eco.Handles.dll

After this has happened Visual Studio has 2 code-bases for the Handles - one the Plugin uses and one the placed Handles in the WindowsForms form use.

This gives us strange exceptions as