Shifting MSA region works wrong with collapsing mode enabled

1. Open "_common_data/scenarios/msa/ma.aln"

2. Enable collapsing mode

3. Select a sequence area including collapsed rows, sequences above and below them

4. Shift selected region

Current state: collapsed regions and sequences above them are shifted properly, the ones below are shifted only for one base and removed from selection.

Also if you select the rows below collapsed only, then shift them, the rows are shifted for one base, then selection moves to collapsed ones and they moves further