diff --git a/examples/basic/periodic.c b/examples/basic/periodic.c
index 2aa6c431..8ff9811e 100644
--- a/examples/basic/periodic.c
+++ b/examples/basic/periodic.c
@@ -341,7 +341,7 @@ int main() {
 	f = frame("Separator", -PaddingContent, -PaddingContent, MwSeparatorClass, NULL);
 
 	f = frame("SubWindow", -PaddingContent, -PaddingContent, MwViewportClass,
-		  MwNcolumnSpan, 2,
+		  MwNcolumnSpan, 3,
 		  NULL);
 	w = child(f);
 	MwViewportSetSize(w, 512, 512);
@@ -352,7 +352,9 @@ int main() {
 			 MwNtitle, "Sub window 2",
 			 NULL);
 
-	f = frame("Tab", -PaddingContent, -PaddingContent, MwTabClass, NULL);
+	f = frame("Tab", -PaddingContent, -PaddingContent, MwTabClass,
+		  MwNcolumnSpan, 2,
+		  NULL);
 	w = child(f);
 	MwSetString(MwTabAdd(w, "ABC"), MwNbackground, "#f00");
 	MwSetString(MwTabAdd(w, "DEF"), MwNbackground, "#0f0");
@@ -364,7 +366,14 @@ int main() {
 	v = MwTreeViewAdd(w, v, NULL, "def");
 	v = MwTreeViewAdd(w, v, NULL, "ghi");
 
-	f = frame("Viewport", -PaddingContent, -PaddingContent, MwViewportClass, NULL);
+	f = frame("Text", -PaddingContent, -PaddingContent, MwViewportClass,
+		  MwNcolumnSpan, 2,
+		  NULL);
+	w = child(f);
+
+	f = frame("Viewport", -PaddingContent, -PaddingContent, MwViewportClass,
+		  MwNcolumnSpan, 2,
+		  NULL);
 	w = child(f);
 	MwViewportSetSize(w, 256, 256);
 	MwVaCreateWidget(MwButtonClass, "btn", MwViewportGetViewport(w), 64, 64, 128, 128,
diff --git a/src/core.c b/src/core.c
index 547b7b1e..0618ea3c 100644
--- a/src/core.c
+++ b/src/core.c
@@ -267,6 +267,8 @@ static MwWidget MwCreateWidget_Internal(MwClass widget_class, const char* name,
 		h->lowlevel = NULL;
 	}
 	h->widget_class	      = widget_class;
+	h->mouse_point.x      = 0;
+	h->mouse_point.y      = 0;
 	h->pressed	      = 0;
 	h->close	      = 0;
 	h->destroy_queue      = NULL;
diff --git a/src/widget/scrollbar.c b/src/widget/scrollbar.c
index 840cdb56..02832a72 100644
--- a/src/widget/scrollbar.c
+++ b/src/widget/scrollbar.c
@@ -27,6 +27,7 @@ static int calc_length(MwWidget handle) {
 	int len	 = MwGetInteger(handle, MwNmaxValue) - MwGetInteger(handle, MwNminValue);
 	int area = MwGetInteger(handle, MwNareaShown);
 	if(area > len) area = len;
+	if(len == 0) return max;
 
 	return (int)(max * (double)area / len);
 }
@@ -35,6 +36,7 @@ static int calc_position(MwWidget handle) {
 	int max = MwScrollBarGetVisibleLength(handle);
 	int len = MwGetInteger(handle, MwNmaxValue) - MwGetInteger(handle, MwNminValue);
 	int val = MwGetInteger(handle, MwNvalue);
+	if(len == 0) return 0;
 
 	return (int)((max - calc_length(handle)) * (double)val / len);
 }
@@ -49,8 +51,10 @@ static void add_value(MwWidget handle, int mul) {
 	if(val < min) val = min;
 	if(val > max) val = max;
 
-	MwSetInteger(handle, MwNvalue, val);
-	MwDispatchUserHandler(handle, MwNchangedHandler, NULL);
+	if(MwGetInteger(handle, MwNvalue) != val) {
+		MwSetInteger(handle, MwNvalue, val);
+		MwDispatchUserHandler(handle, MwNchangedHandler, NULL);
+	}
 }
 
 static void draw(MwWidget handle) {
@@ -223,6 +227,7 @@ static void mouse_down(MwWidget handle, void* ptr) {
 static void prop_change(MwWidget handle, const char* key) {
 	if(strcmp(key, MwNminValue) == 0 || strcmp(key, MwNvalue) == 0 || strcmp(key, MwNmaxValue) == 0) {
 		if(MwGetInteger(handle, MwNvalue) > MwGetInteger(handle, MwNmaxValue)) MwSetInteger(handle, MwNvalue, MwGetInteger(handle, MwNmaxValue));
+		if(MwGetInteger(handle, MwNvalue) < MwGetInteger(handle, MwNminValue)) MwSetInteger(handle, MwNvalue, MwGetInteger(handle, MwNminValue));
 		MwForceRender(handle);
 	}
 	if(strcmp(key, MwNshowArrows) == 0 || strcmp(key, MwNareaShown) == 0) {