Filter removing checkboxes from results

[Ikkoru]

Typing certain character into the "Search" filter removes all or some checkboxes, as well as the ability to mark duplicate items.

The following characters have the following effects:
q (2 checkmarks removed near the bottom of the list);
w (3 checkmarks removed near the top of the list);
y (3 checkmarks removed near the top of the list);
f (7 checkmarks removed near the bottom of the list);
k (1 checkmarks removed near the top of the list);
; (3 checkmarks removed near the bottom of the list);
' (1 checkmarks removed near the bottom of the list);
x (A LOT all over the list!!!);
b (9 checkmarks removed near the bottom of the list).

This is with the setting of "Use regular expressions when filtering" OFF.

EDIT: Seems it's a bit more complicated than just specific letters having specific effects...
v] (removes almost every checkbox).