Nothing is perfect... and the WF Designer is not even close.  The juggernaut that is Microsoft is not an exception either.  So, when I pulled my hair out all day figuring out why a type "Services.Jobs.Job" didn't equate to a type of "Services.Jobs.Job", I was pleased to find out that Microsoft's mistakes are fixable.

The actual error I got was this:

Path resolved to Referenced activity Property 'Job' whose PropertyType 'Services.Jobs.Job' does not match with the Target Type 'Services.Jobs.Job'.

This is frustrating.   Where to begin.  Naturally, I tend to think that I am losing my mind when I see bugs like this, then I actually do lose it trying to fix them.  Long story short... this fixed it for me:

1. Closed all WF designers
2. Cleaned My Solution
3. Closed all Visual Studio instances
4. Deleted everything in my %temp% directory. (WINDOWS-R, then type %temp%)
5. Deleted the .suo file associated with my solution.
6. Restarted Visual Studio and Rebuilt my application

Now, I don't know which step was critical here, but Steps 1-3 by themselves didn't work for me.