SearchAndSelect removes results twice

[ri-pandey]

Reproduction steps (see attached GIF for visual reproduction of these steps):

1. Click Add button and open DatasetSelect widget. Total Count in the right (Datasets to Assign) table is 12.
2. Add a search result. Total Count in the right (Datasets to Assign) table should be increased to 13.
3. Remove a search result from the right (Datasets to Assign) table. Total Count in the right (Datasets to Assign) table decreased to 11 instead of 12.