Code [patched] | Pointer Focus Registration

Test on synthetic events. Log your transitions. And for the love of all that is responsive, never, ever call register_pointer_focus inside a layout pass.

is the exclusive right of a single UI element to receive input events originating from a pointing device (mouse, pen, touch). Unlike keyboard focus (which can be transferred via Tab ), pointer focus is transient, aggressive, and inherently tied to geometry and z-order. pointer focus registration code

case WM_MOUSEMOVE: SetFocus(hwnd); You write: Test on synthetic events

The best systems make pointer focus invisible. The worst make it unforgettable. is the exclusive right of a single UI

By a recovering systems programmer

But beneath that click lies a silent negotiation—a race condition waiting to happen, a state machine ready to deadlock, and a chain of event propagation that would make a network engineer wince.