Most windows allow you to press keys either
•to edit your data (edit mode), or
•to get quickly to a place in a list (type-in mode)
•to set a category.
Concordance windows use key presses also blanking out the search word.
In type-in mode, your key-presses are supposed to help you get quickly to the list item you're interested in, e.g by typing theocr to get to (or near to) theocracy in a word list. If you've typed in 5 letters and a match is found, the search stops.
Changing mode can be done using T (type-in) or S (set) buttons in the status-bar
(here the darker colour T button shows the current setting is type-in mode) or via the menu: Settings | Typing Mode:
See also: user-defined categories.