You need that to do drag and drop with one mouse-down and one mouse-up.
Given that, the designer can decide if that’s an exception and everything else requires click-to-focus before being interactive, or to use focus-follows-mouse. People really seem to have individual preferences on this, so there’s no one right answer.
Given that, the designer can decide if that’s an exception and everything else requires click-to-focus before being interactive, or to use focus-follows-mouse. People really seem to have individual preferences on this, so there’s no one right answer.