WM_NCXBUTTONDBLCLK top-level constant
int
const WM_NCXBUTTONDBLCLK
Posted when the user double-clicks the first or second X button while the cursor is in the nonclient area of a window.
This message is posted to the window that contains the cursor. If a window has captured the mouse, this message is not posted.
To learn more, see learn.microsoft.com/windows/win32/inputdev/wm-ncxbuttondblclk.
Implementation
const WM_NCXBUTTONDBLCLK = 173;