How can I change behavior of how items are selected in QGridLayout by cursor keys? I want to move selection horizontally by left/right cursor keys and vertically by up/down keys.
Who is responsible for it? Layout, items container or tab order?
You can reimplement keyPressEvent() method for the main widget to catch the pressed keys. Then you can access the desired widget in your layout by calling QGridLayout::itemAtPosition (int row, int column) and then set focus to it.
Custom QGridLayout items selection behaviour