Crash on save subalignment

The crash occurs in the following scenario:

1. Open general/common_data/nexus/DQB1_exon4.nexus
2. Set collapsing mode on
3. Rename the last two sequences in seqA and seqB
4. Copy seqA
5. Select first collapsed mode and click Edit->Paste before
6. Cut seqB
7. Select the first sequence and click Edit->Paste before
8. Select seqB and seqA
9. Export->Save subalignment
10. Click OK in the dialog
    Expected state: Save subalignment seqB and seqA(collapsed)
    Actual state:

    Promoting task {Create sub-alignment and open view: DQB1_exon4.nexus} to 'Prepared'
    No row ID '42' in 'DQB1_exon4' alignment!
    Failed to crop an alignment!
    Trying to recover from error: Failed to crop an alignment! at D:\ugene\ugene\src\corelibs\U2Core\src\gobjects\MultipleSequenceAlignmentObject.cpp:151
    Assertion failed: 0, file D:\ugene\ugene\src\corelibs\U2Core\src\gobjects\MultipleSequenceAlignmentObject.cpp, line 151