End / Delete Task / edit users of task on locked tasks

1. User A opens the taskoverview and gets the task X.
2. User B locks the same task by opening it.
   • if User A reloads the tasks, the icons delete, end and edit users of task will disappear
   • if User A does NOT reload the tasks, the above icons will remain.
   • User A can then delete / end / edit the users of the task, although the task is locked.

=> test which combination of locked tasks by one user with not up2date task-grid by another user leads to which problems / messages (for all possible action icons)
=> same for soap-api
=> make proposals, how to solve this