Selection with arrow keys & Shift works differently in the names list & sequence area

Scenario:

1. Open any alignment.
2. Click on the sequence area
3. Press Shift + Up/Down keys.
   Expected result: the selection is extended.
4. Click on any sequence in the name list.
5. Press Shift + Up/Down keys.
   Expected result: the same as on the step 3.
   Current result: nothing happens.