Mention's drop down does not get displayed the second time if there are no results

Steps to reproduce:

1. Go to any fields with mentions
2. Start typing a mention that returns no results (lets say '@x')
3. You get the 'No results' message
4. Delete the 'x'
5. Mentions drop down is gone
6. Write 'x' again

Expected result: you should get the 'No results' message again (same as step 3).
Current result: you don't get the mentions dialog at all.