Posted when a pointer makes contact over the client area of a window. This input message targets the window over which the pointer makes contact, and the pointer is implicitly captured to the window so that the window continues to receive input for the pointer until it breaks contact. A window receives this message through its WindowProc function. ![Important] Desktop apps should be DPI aware. If
![WM_POINTERDOWN message - Win32 apps](https://cdn-ak-scissors.b.st-hatena.com/image/square/d6e4cb632c7025e9f5e05fd314fbf6dcd6144e8d/height=288;version=1;width=512/https%3A%2F%2Flearn.microsoft.com%2Fen-us%2Fmedia%2Fopen-graph-image.png)