WM_NCLBUTTONDBLCLK
nHittest = wParam; /* hit-test code */
xCursor = LOWORD(lParam); /* cursor horizontal position */
yCursor = HIWORD(lParam); /* cursor vertical position */
The WM_NCLBUTTONDBLCLK message is sent when the user double-clicks the left mouse button while the cursor is within a nonclient area of the window.
nHittest
Value of wParam. Specifies the code returned by WM_NCHITTEST. For more information, see the description of the WM_NCHITTEST message.
xCursor
Value of the low-order word of lParam. Specifies the horizontal position of the cursor, in screen coordinates.
yCursor
Value of the high-order word of lParam. Specifies the vertical position of the cursor, in screen coordinates.
An application should return zero if it processes this message.
If appropriate, WM_SYSCOMMAND messages are sent.