mouse buttons are released on top of FRAME.
This function will sometimes return immediately if no mouse buttons
-are currently held down, and should only be called in situations where
-it is known that some are being held down down, such as immediately
-after a `down-mouse-1' event. */)
+are currently held down. It should only be called when it is known
+that mouse buttons are being held down, such as immediately after a
+`down-mouse-1' (or similar) event. */)
(Lisp_Object targets, Lisp_Object action, Lisp_Object frame,
Lisp_Object return_frame, Lisp_Object allow_current_frame)
{