The "Redo" button is enabled unexpectedly after column removing

Scenario to reproduce:

1. Open "data/sample/CLUSTALW/COI.aln".
2. Select {Edit -> Remove columns of gaps...}

   menu item from the context menu.

3. Select the "all-gaps columns" option and accept the dialog.
   Expected state: nothing happens.
   Current state: the "redo" button becames enabled.