user32: Pass a NULL rectangle in the ClipCursor entry point when clipping is…

dlls/user32/message.c

@@ -1870,11 +1870,13 @@ static LRESULT handle_internal_message( HWND hwnd, UINT msg, WPARAM wparam, LPAR
         return call_current_hook( h_extra->handle, HC_ACTION, wparam, h_extra->lparam );
     }
     case WM_WINE_CLIPCURSOR:
+        if (wparam)
         {
             RECT rect;
             GetClipCursor( &rect );
             return USER_Driver->pClipCursor( &rect );
         }
+        return USER_Driver->pClipCursor( NULL );
     default:
         if (msg >= WM_WINE_FIRST_DRIVER_MSG && msg <= WM_WINE_LAST_DRIVER_MSG)
             return USER_Driver->pWindowMessage( hwnd, msg, wparam, lparam );

server/queue.c

@@ -354,9 +354,9 @@ static void set_clip_rectangle( struct desktop *desktop, const rectangle_t *rect
 
     get_top_window_rectangle( desktop, &top_rect );
     if (!rect || !intersect_rect( &new_rect, &top_rect, rect )) new_rect = top_rect;
-    if (!memcmp( &desktop->cursor.clip, &new_rect, sizeof(new_rect) )) return;
     desktop->cursor.clip = new_rect;
-    if (desktop->cursor.clip_msg) post_desktop_message( desktop, desktop->cursor.clip_msg, 0, 0 );
+    if (desktop->cursor.clip_msg)
+        post_desktop_message( desktop, desktop->cursor.clip_msg, rect != NULL, 0 );
 
     /* warp the mouse to be inside the clip rect */
     x = min( max( desktop->cursor.x, desktop->cursor.clip.left ), desktop->cursor.clip.right-1 );