Attempt to make Windows pointer hiding more robust by ignoring MOUSEMOVE and

NCMOUSEMOVE messages where nothing actually changes. It seems Windows likes
to send such messages occasionally when other stuff is going on (e.g., in
other windows).
(Also spotted by Franco Barber <20040122055232.GA8168@febsun.cmhnet.org>.)

[originally from svn r4358]

window.c

@@ -1721,6 +1721,7 @@ static LRESULT CALLBACK WndProc(HWND hwnd, UINT message,
     static int ignore_clip = FALSE;
     static int need_backend_resize = FALSE;
     static int fullscr_on_max = FALSE;
+    static UINT last_mousemove = 0;
 
     switch (message) {
       case WM_TIMER:
@@ -2160,7 +2161,21 @@ static LRESULT CALLBACK WndProc(HWND hwnd, UINT message,
 	}
 	return 0;
       case WM_MOUSEMOVE:
-	show_mouseptr(1);
+	{
+	    /*
+	     * Windows seems to like to occasionally send MOUSEMOVE
+	     * events even if the mouse hasn't moved. Don't unhide
+	     * the mouse pointer in this case.
+	     */
+	    static WPARAM wp = 0;
+	    static LPARAM lp = 0;
+	    if (wParam != wp || lParam != lp ||
+		last_mousemove != WM_MOUSEMOVE) {
+		show_mouseptr(1);
+		wp = wParam; lp = lParam;
+		last_mousemove = WM_MOUSEMOVE;
+	    }
+	}
 	/*
 	 * Add the mouse position and message time to the random
 	 * number noise.
@@ -2183,7 +2198,16 @@ static LRESULT CALLBACK WndProc(HWND hwnd, UINT message,
 	}
 	return 0;
       case WM_NCMOUSEMOVE:
-	show_mouseptr(1);
+	{
+	    static WPARAM wp = 0;
+	    static LPARAM lp = 0;
+	    if (wParam != wp || lParam != lp ||
+		last_mousemove != WM_NCMOUSEMOVE) {
+		show_mouseptr(1);
+		wp = wParam; lp = lParam;
+		last_mousemove = WM_NCMOUSEMOVE;
+	    }
+	}
 	noise_ultralight(lParam);
 	break;
       case WM_IGNORE_CLIP: