note: Normally I'd just submit the updated sample back through the community site but it never seems to not explode for me so I am posting this patch here.
This is a small set of patches to the excellent Dynamic Invoke Workflow activity off the NetFx site. For those of you in the know, it's a custom activity that allows you to run a child workflow but defer the exact type of workflow until runtime. This sure as hell makes it easier to accomplish than dynamically adding activities to a WorkflowChanges object (especially as you need to figure out how to wire up the dependancy properties).
While this activity works like a champ, the lack of designer support makes it seem a little chinsy. So I spent a few minutes and knocked out some basic designer support (thankfully there really isn't much to be had). To use, simply add my designer classes to your copy of the custom activity project and add the following attributes to the activity class declaration like this:
[ToolboxBitmap(typeof(CustomInvokeWorkflowActivity), "ToolboxIcon.bmp")]
[DesignerAttribute(typeof(CustomInvokeWorkflowActivityDesigner), typeof(IDesigner))]
I've added support for custom icons and supplied a distinct theme. Feel free to take as you need and run with it! Here's a screen shot of what to expect (I personally like the modified InvokeWorkflow icon):

Download the code |