opengl32: Mark invalid handles with ffff instead of 0.
diff --git a/dlls/opengl32/wgl.c b/dlls/opengl32/wgl.c
index 815dc42..4545cfa 100644
--- a/dlls/opengl32/wgl.c
+++ b/dlls/opengl32/wgl.c
@@ -164,7 +164,7 @@
 
 static void free_handle_ptr( struct wgl_handle *ptr )
 {
-    ptr->handle &= ~0xffff;
+    ptr->handle |= 0xffff;
     ptr->context = (struct wgl_context *)next_free;
     ptr->funcs = NULL;
     next_free = ptr;