Regression: a part of pattern can be found in Alignment Editor

Scenario

1. Open "data/samples/CLUSTALW/COI.aln".
2. Select last 10 bases of the first 10 rows.
3. Press the Space key.
   Expected state: the selected region is shifted.
4. Press Ctr+f, enter the following pattern: "ACCCTATTTTATACCAACAAACTare", press Enter.
   Expected state: nothing happens, the pattern is not found, the selection is not changed.
   Current state: there is a result: "ACCCTA----------TTTTATACCA".

Affected GUI test

GUITest_regression_scenarios_test_4013.