Incorrect annotation handling on the sequence crop

Scenario to reproduce:

1. Create a sequence "CCCCC".
2. Search all possible enzymes.
3. Remove sequence region (2..5), crop corresponding annotations.
   Expected state: there is a sequence "C" with some annotations, there is no messages in the log.
   Current state: one annotation has region (2..1), if you choose it, safe point triggers.

If you try to do something with this annotation you can get a crash, e.g. export sequence region that corresponds the annotation.