QCompleter sets current completion with no user interaction

Current completion in QCompleter is being set sporadically as there's any match to the user input in parent widget — even with no user interaction with QCompleter popup itself. The problem seems to be in qtbase/src/widgets/util/qcompleter.cpp:449, where curRow is forcefully set to 0 if any match was found.

This issue leads not only to incorrect currentCompletion() return, but also to false-positive activated() signal firing which in turn usually leads to double activated() signal calling in parent widget.