Description of problem:
When an element in the process designer is locked using the "lock process part" feature then it's not possible to select a single element using the left mouse button and unlock it.

Version-Release number of selected component (if applicable):
Upstream Beta5

How reproducible:
1) create a process containing a start node and a end node.
2) select the whole process and use the lock feature.
3) now try to select the start node using the left mouse button