I created a custom Visual Studio Workflow. It works fine and is a simple approval workflow.
There is a Workflow Task associated to a dynamic user and the user musst approve or reject it.
The Problem is, that the approving user can still access the form after completing the task and make changes...
I use the built-in approval form:
So, even if the Task is completed, the approver can change the approval status of the item.
How to prevent him from that?