diff --git a/stack.c b/stack.c
index 80c2d75c..f65e0d74 100644
--- a/stack.c
+++ b/stack.c
@@ -1,13 +1,17 @@
 // 7 april 2015
 #include "uipriv.h"
 
+// TODO
+// - use stackControl
+// - change prefwid/prefht to preferredWidth/preferredHeight
+
 typedef struct stack stack;
+typedef struct stackControl stackControl;
 
 struct stack {
-	uiControl control;
 	uiControl **controls;
 	int *stretchy;
-	intmax_t *width;		// both used by resize(); preallocated to save time and reduce risk of failure
+	intmax_t *width;
 	intmax_t *height;
 	uintmax_t len;
 	uintmax_t cap;
@@ -16,20 +20,26 @@ struct stack {
 	int padded;
 };
 
-#define S(c) ((stack *) (c))
+struct stackControl {
+	uiControl *control;
+	int stretchy;
+	intmax_t width;		// both used by resize(); preallocated to save time and reduce risk of failure
+	intmax_t height;
+};
 
 static void stackDestroy(uiControl *c)
 {
-	stack *s = (stack *) c;
+	stack *s = (stack *) (c->data);
 	uintmax_t i;
 
-	for (i = 0; i < S(c)->len; i++)
+	for (i = 0; i < s->len; i++)
 		uiControlDestroy(s->controls[i]);
 	uiFree(s->controls);
 	uiFree(s->stretchy);
 	uiFree(s->width);
 	uiFree(s->height);
 	uiFree(s);
+	uiFree(c);
 }
 
 static uintptr_t stackHandle(uiControl *c)
@@ -39,56 +49,55 @@ static uintptr_t stackHandle(uiControl *c)
 
 static void stackSetParent(uiControl *c, uintptr_t parent)
 {
-	stack *s = S(c);
+	stack *s = (stack *) (c->data);
 	uintmax_t i;
 
 	s->parent = parent;
-	for (i = 0; i < S(c)->len; i++)
-		(*(s->controls[i]->setParent))(s->controls[i], s->parent);
+	for (i = 0; i < s->len; i++)
+		uiControlSetParent(s->controls[i], s->parent);
 	updateParent(s->parent);
 }
 
 static void stackRemoveParent(uiControl *c)
 {
-	stack *s = S(c);
+	stack *s = (stack *) (c->data);
 	uintmax_t i;
 	uintptr_t oldparent;
 
 	oldparent = s->parent;
 	s->parent = 0;
-	for (i = 0; i < S(c)->len; i++)
-		(*(s->controls[i]->removeParent))(s->controls[i]);
+	for (i = 0; i < s->len; i++)
+		uiControlRemoveParent(s->controls[i]);
 	updateParent(oldparent);
 }
 
-static uiSize stackPreferredSize(uiControl *c, uiSizing *d)
+static void stackPreferredSize(uiControl *c, uiSizing *d, intmax_t *width, intmax_t *height)
 {
-	stack *s = S(c);
+	stack *s = (stack *) (c->data);
 	int xpadding, ypadding;
 	uintmax_t nStretchy;
 	intmax_t maxswid, maxsht;
 	uintmax_t i;
-	uiSize size, preferred;
-	uiSizingComm *dd = (uiSizingComm *) d;
+	intmax_t prefwid, prefht;
 
-	size.width = 0;
-	size.height = 0;
+	*width = 0;
+	*height = 0;
 	if (s->len == 0)
-		return size;
+		return;
 
 	// 0) get this Stack's padding
 	xpadding = 0;
 	ypadding = 0;
 	if (s->padded) {
-		xpadding = dd->xPadding;
-		ypadding = dd->yPadding;
+		xpadding = d->xPadding;
+		ypadding = d->yPadding;
 	}
 
 	// 1) initialize the desired rect with the needed padding
 	if (s->vertical)
-		size.height = (s->len - 1) * ypadding;
+		*height = (s->len - 1) * ypadding;
 	else
-		size.width = (s->len - 1) * xpadding;
+		*width = (s->len - 1) * xpadding;
 
 	// 2) add in the size of non-stretchy controls and get (but not add in) the largest widths and heights of stretchy controls
 	// we still add in like direction of stretchy controls
@@ -96,45 +105,42 @@ static uiSize stackPreferredSize(uiControl *c, uiSizing *d)
 	maxswid = 0;
 	maxsht = 0;
 	for (i = 0; i < s->len; i++) {
-		preferred = (*(s->controls[i]->preferredSize))(s->controls[i], d);
+		uiControlPreferredSize(s->controls[i], d, &prefwid, &prefht);
 		if (s->stretchy[i]) {
 			nStretchy++;
-			if (maxswid < preferred.width)
-				maxswid = preferred.width;
-			if (maxsht < preferred.height)
-				maxsht = preferred.height;
+			if (maxswid < prefwid)
+				maxswid = prefwid;
+			if (maxsht < prefht)
+				maxsht = prefht;
 		}
 		if (s->vertical) {
-			if (size.width < preferred.width)
-				size.width = preferred.width;
+			if (*width < prefwid)
+				*width = prefwid;
 			if (!s->stretchy[i])
-				size.height += preferred.height;
+				*height += prefht;
 		} else {
 			if (!s->stretchy[i])
-				size.width += preferred.width;
-			if (size.height < preferred.height)
-				size.height = preferred.height;
+				*width += prefwid;
+			if (*height < prefht)
+				*height = prefht;
 		}
 	}
 
 	// 3) and now we can add in stretchy controls
 	if (s->vertical)
-		size.height += nStretchy * maxsht;
+		*height += nStretchy * maxsht;
 	else
-		size.width += nStretchy * maxswid;
-
-	return size;
+		*width += nStretchy * maxswid;
 }
 
 static void stackResize(uiControl *c, intmax_t x, intmax_t y, intmax_t width, intmax_t height, uiSizing *d)
 {
-	stack *s = S(c);
+	stack *s = (stack *) (c->data);
 	int xpadding, ypadding;
 	uintmax_t nStretchy;
 	intmax_t stretchywid, stretchyht;
 	uintmax_t i;
-	uiSize preferred;
-	uiSizingComm *dd = (uiSizingComm *) d;
+	intmax_t prefwid, prefht;
 
 	if (s->len == 0)
 		return;
@@ -143,8 +149,8 @@ static void stackResize(uiControl *c, intmax_t x, intmax_t y, intmax_t width, in
 	xpadding = 0;
 	ypadding = 0;
 	if (s->padded) {
-		xpadding = dd->xPadding;
-		ypadding = dd->yPadding;
+		xpadding = d->xPadding;
+		ypadding = d->yPadding;
 	}
 
 	// 0) inset the available rect by the needed padding
@@ -164,15 +170,15 @@ static void stackResize(uiControl *c, intmax_t x, intmax_t y, intmax_t width, in
 			continue;
 		}
 		c = s->controls[i];
-		preferred = (*(s->controls[i]->preferredSize))(s->controls[i], d);
+		uiControlPreferredSize(s->controls[i], d, &prefwid, &prefht);
 		if (s->vertical) {		// all controls have same width
 			s->width[i] = width;
-			s->height[i] = preferred.height;
-			stretchyht -= preferred.height;
+			s->height[i] = prefht;
+			stretchyht -= prefht;
 		} else {				// all controls have same height
-			s->width[i] = preferred.width;
+			s->width[i] = prefwid;
 			s->height[i] = height;
-			stretchywid -= preferred.width;
+			stretchywid -= prefwid;
 		}
 	}
 
@@ -190,7 +196,7 @@ static void stackResize(uiControl *c, intmax_t x, intmax_t y, intmax_t width, in
 
 	// 3) now we can position controls
 	for (i = 0; i < s->len; i++) {
-		(*(s->controls[i]->resize))(s->controls[i], x, y, s->width[i], s->height[i], d);
+		uiControlResize(s->controls[i], x, y, s->width[i], s->height[i], d);
 		if (s->vertical)
 			y += s->height[i] + ypadding;
 		else
@@ -200,26 +206,31 @@ static void stackResize(uiControl *c, intmax_t x, intmax_t y, intmax_t width, in
 
 uiControl *uiNewHorizontalStack(void)
 {
+	uiControl *c;
 	stack *s;
 
+	c = uiNew(uiControl);
 	s = uiNew(stack);
 
-	s->control.destroy = stackDestroy;
-	s->control.handle = stackHandle;
-	s->control.setParent = stackSetParent;
-	s->control.removeParent = stackRemoveParent;
-	s->control.preferredSize = stackPreferredSize;
-	s->control.resize = stackResize;
+	c->data = s;
+	c->destroy = stackDestroy;
+	c->handle = stackHandle;
+	c->setParent = stackSetParent;
+	c->removeParent = stackRemoveParent;
+	c->preferredSize = stackPreferredSize;
+	c->resize = stackResize;
 
-	return (uiControl *) s;
+	return c;
 }
 
 uiControl *uiNewVerticalStack(void)
 {
 	uiControl *c;
+	stack *s;
 
 	c = uiNewHorizontalStack();
-	S(c)->vertical = 1;
+	s = (stack *) (c->data);
+	s->vertical = 1;
 	return c;
 }
 
@@ -227,7 +238,7 @@ uiControl *uiNewVerticalStack(void)
 
 void uiStackAdd(uiControl *st, uiControl *c, int stretchy)
 {
-	stack *s = S(st);
+	stack *s = (stack *) (st->data);
 
 	if (s->len >= s->cap) {
 		s->cap += stackCapGrow;
@@ -246,9 +257,9 @@ void uiStackAdd(uiControl *st, uiControl *c, int stretchy)
 
 // TODO get padded
 
-void uiStackSetPadded(uiControl *st, int padded)
+void uiStackSetPadded(uiControl *c, int padded)
 {
-	stack *s = S(st);
+	stack *s = (stack *) (c->data);
 
 	s->padded = padded;
 	updateParent(s->parent);