This message occurs when the user presses the right mouse button.
| Parameter | Description |
| wParam | Contains a value that indicates whether various virtual keys are down. It can be any combination of the following values: | ||
| Value | Meaning | ||
| MK_CONTROL | Set if CONTROL key is down. | ||
| MK_LBUTTON | Set if left button is down. | ||
| Parameter | Description | ||
| Value | Meaning | ||
| MK_MBUTTON | Set if middle button is down. | ||
| MK_SHIFT | Set if SHIFT key is down. | ||
| lParam | Contains the x- and y-coordinates of the cursor. The x-coordinate is in the low-order word; the y-coordinate is in the high-order word. These coordinates are always relative to the upper-left corner of the window. | ||