The problem, as I see it, is that the object ID of the current node is passed as second parameter to removeAssignment(), no matter if it is the currect node we are removing, or a child node. The object ID is used to fetch node assignments for the node to remove, with eZNodeAssignment::fetchForObject(). But in step 3, it will fetch assigments of the parent of the node I'm removing, with the consequence that no assignments will be removed. (It doesn't remove the wrong assignments - that's good!)

The attached patch fixes this.

(4.0 is not affected.)

Steps to reproduce

Step 1: Create an object with 3 nodes.
Step 2: View one of the nodes (node/view/full). Click "Remove". Check that the node assignment was removed in the DB - this works.
Step 3: View the parent of one of the other nodes. Select the node using the checkbox, and click "Remove selected". Check that the node assignment was removed in the DB - this does not work.