I wanted to mark my already existing task T86167: Create labs project for CI disposables instances as a blocker. I thus:
- head to T76375
- click 'Edit Blocking Tasks'
- fill T86167
- click select button
- click Save Blocking Tasks
The window disappear but the main page remain greyed out.
After a few attempt it eventually worked though. It was probably a transient error, I am filling this task in case someone wants to investigate. Otherwise just decline this task :]