diff --git a/components/rtgui/common/dc_client.c b/components/rtgui/common/dc_client.c
index 6dcf3181c04080b669f27edff4a3d842657d527b..15360501c92bf296f0ffcb61d8f64e7489d634a7 100644
--- a/components/rtgui/common/dc_client.c
+++ b/components/rtgui/common/dc_client.c
@@ -42,6 +42,8 @@ static void rtgui_dc_client_get_rect(struct rtgui_dc* dc, rtgui_rect_t* rect);
 
 struct rtgui_dc* rtgui_dc_begin_drawing(rtgui_widget_t* owner)
 {
+	RT_ASSERT(owner != RT_NULL);
+
 	if ((rtgui_region_is_flat(&owner->clip) == RT_EOK) && 
 		rtgui_rect_is_equal(&(owner->extent), &(owner->clip.extents)) == RT_EOK)
 	{
diff --git a/components/rtgui/common/rtgui_theme.c b/components/rtgui/common/rtgui_theme.c
index 266ceea9c91793859545f07d9039e69e91283078..e328f19f0bac44dfc542fe93ce18bd5a180b3862 100644
--- a/components/rtgui/common/rtgui_theme.c
+++ b/components/rtgui/common/rtgui_theme.c
@@ -58,6 +58,8 @@ void rtgui_theme_draw_win(struct rtgui_topwin* win)
 	struct rtgui_dc* dc;
 	rtgui_rect_t rect;
 
+	if (win->title == RT_NULL) return; /* no title and no board */
+
 	/* begin drawing */
 	dc = rtgui_dc_begin_drawing(RTGUI_WIDGET(win->title));
 	if (dc == RT_NULL) return;
diff --git a/components/rtgui/widgets/widget.c b/components/rtgui/widgets/widget.c
index 81968f929d18aa6fda456150761171443b0391ce..34b022c04a7e0fd40553f63c62ebe12fe2a53795 100644
--- a/components/rtgui/widgets/widget.c
+++ b/components/rtgui/widgets/widget.c
@@ -134,7 +134,7 @@ void rtgui_widget_set_rect(rtgui_widget_t* widget, rtgui_rect_t* rect)
 	if ((widget->parent != RT_NULL) && (widget->toplevel != RT_NULL))
 	{
 		/* update widget clip */
-		rtgui_widget_update_clip(widget);
+		rtgui_widget_update_clip(widget->parent);
 	}
 }
 
@@ -417,7 +417,15 @@ void rtgui_widget_update_clip(rtgui_widget_t* widget)
 
 	parent = widget->parent;
 	/* if there is no parent, do not update clip (please use toplevel widget API) */
-	if (parent == RT_NULL) return;
+	if (parent == RT_NULL)
+	{
+		if (RTGUI_IS_TOPLEVEL(widget))
+		{
+			/* if it's toplevel widget, update it by toplevel function */
+			rtgui_toplevel_update_clip(RTGUI_TOPLEVEL(widget));
+		}
+		return;
+	}
 
 	/* reset clip to extent */
 	rtgui_region_reset(&(widget->clip), &(widget->extent));