A GUI Deadlock on annotation groups search during Smith-Waterman task run

Scenario to reproduce:

1. Open "data/samples/FASTA/human_T1.fa".
2. Create at least two annotation groups with annotations.
3. Start Smith-Waterman search with any valid pattern and default settings.
4. Until search task doesn't finish, click "Find annotated regions" button on the toolbar.
5. Set two annotation groups and start the search.
   Current state: a deadlock occurs: you can't stop the task and close the dialog.