win32u: Add a clipping_cursor member to user_thread_info.

dlls/win32u/input.c

@@ -404,6 +404,7 @@ static const KBDTABLES kbdus_tables =
     .fLocaleFlags = MAKELONG(0, KBD_VERSION),
 };
 
+static LONG clipping_cursor; /* clipping thread counter */
 
 LONG global_key_state_counter = 0;
 BOOL grab_pointer = TRUE;
@@ -2504,6 +2505,9 @@ BOOL process_wine_clipcursor( BOOL empty, BOOL reset )
 
     TRACE( "empty %u, reset %u\n", empty, reset );
 
+    if (thread_info->clipping_cursor) InterlockedDecrement( &clipping_cursor );
+    thread_info->clipping_cursor = FALSE;
+
     if (reset)
     {
         thread_info->clipping_reset = NtGetTickCount();
@@ -2514,7 +2518,10 @@ BOOL process_wine_clipcursor( BOOL empty, BOOL reset )
     if (empty) return user_driver->pClipCursor( NULL, reset );
 
     get_clip_cursor( &rect );
-    return user_driver->pClipCursor( &rect, FALSE );
+    if (!user_driver->pClipCursor( &rect, FALSE )) return FALSE;
+    InterlockedIncrement( &clipping_cursor );
+    thread_info->clipping_cursor = TRUE;
+    return TRUE;
 }
 
 /***********************************************************************

dlls/win32u/ntuser_private.h

@@ -130,6 +130,7 @@ struct user_thread_info
     UINT                          kbd_layout_id;          /* Current keyboard layout ID */
     struct rawinput_thread_data  *rawinput;               /* RawInput thread local data / buffer */
     UINT                          spy_indent;             /* Current spy indent */
+    BOOL                          clipping_cursor;        /* thread is currently clipping */
     DWORD                         clipping_reset;         /* time when clipping was last reset */
 };