title: Workflow Custom Activity building workflow parameters
body: <p>Let's say I have a Workflow with 2 dependency Property : Prop1, Prop2.</p>
  
  <p>I'd like to create a custom activity that when I drag into the workflow, It will show Prop1 and Prop2 in the property grid in the designer. </p>
  
  <p>Is this possible ? </p>
  
  <p>Like the invokeWorkflow, when you select the TargetWorkflow, it populates the property grid with Parameters of the workflow, so that you can bind.</p>