"Search field" in the SV is not updated when "Search with ambiguous bases" is checked

Scenario:

1. Open a DNA sequence in the SV.
2. Open the "Search in Sequence" tab on the options panel.
3. Set algorithm to "Substitute" in the "Search algorithm" group.
4. Input a pattern that contains a character of the extended DNA alphabet, e.g. "ACWT".
   Expected/current result: the search field background is red. There is a message below:

   Warning: input value contains characters that do not match the active alphabet!
   

5. Make the "Search with ambiguous bases" option checked.
   Expected result: the search field should have white background, the warning message should disappear.
   Current result: nothing happens.

Note that the tab appearance is updated, if you e.g. input a space character smth into the search field.