Cannot update 'Child' task under SR

Hi,

I have a question about the relationship between 'child' and 'parent' tasks in Service module of OeBS.

We often create Service Request with some tasks connected with it. Tasks are sometimes divided for the 'parent' task and 'child' tasks (under the same SR).

For most of the 'child' tasks it is not possible afterwards to change Status or Assignee (the fields are greyed out as in the attachment). It is still however possible to change everything in the 'parent' task or any other task which is not under 'parent'-'child' relationship (as long as SR status is not 'Closed' or 'Cancelled').