diff --git a/darwin/box.m b/darwin/box.m
index c41ab6f1..25116c5e 100644
--- a/darwin/box.m
+++ b/darwin/box.m
@@ -95,9 +95,9 @@ struct uiBox {
 			self->secondaryOrientation = NSLayoutConstraintOrientationVertical;
 		}
 
-		// TODO default high?
-		self->horzHuggingPri = NSLayoutPriorityRequired;
-		self->vertHuggingPri = NSLayoutPriorityRequired;
+		// TODO required?
+		self->horzHuggingPri = NSLayoutPriorityDefaultHigh;
+		self->vertHuggingPri = NSLayoutPriorityDefaultHigh;
 	}
 	return self;
 }
@@ -132,7 +132,7 @@ struct uiBox {
 	[self removeConstraints:self->inBetweens];
 	[self->inBetweens removeAllObjects];
 	[self removeConstraint:self->last];
-	[self removeConstraint:self->lastHugging];
+	[self removeConstraint:self->last2];
 	[self removeConstraints:self->otherConstraints];
 	[self->otherConstraints removeAllObjects];
 }
@@ -300,7 +300,7 @@ struct uiBox {
 		// TODO will default high work?
 		uiDarwinControlSetRealHuggingPriority(uiDarwinControl(bc.c), NSLayoutPriorityRequired, self->primaryOrientation);
 	// make sure controls don't hug their secondary direction so they fill the width of the view
-	uiDarwinControlSetRealHuggingPriority(uiDarwinControl(bc.c), NSLayoutPriorityDefaultLow, self->secondaryOrientation);
+	uiDarwinControlSetRealHuggingPriority(uiDarwinControl(bc.cc), NSLayoutPriorityDefaultLow, self->secondaryOrientation);
 
 	[self->children addObject:bc];
 	[bc release];		// we don't need the initial reference now
diff --git a/darwin/group.m b/darwin/group.m
index 1fbce07b..663c58cd 100644
--- a/darwin/group.m
+++ b/darwin/group.m
@@ -70,9 +70,27 @@ static void uiGroupSyncEnableState(uiDarwinControl *c, int enabled)
 
 uiDarwinControlDefaultSetSuperview(uiGroup, box)
 
-static void uiGroupSetRealHuggingPriority(uiDarwinControl *c, NSLayoutPriority priority, NSLayoutConstraintOrientation orientation)
+static BOOL uiGroupChildrenShouldAllowSpaceAtTrailingEdge(uiDarwinControl *c)
 {
-	// TODO
+	uiControl *parent;
+
+	// TODO figure out why this works
+	parent = uiControlParent(uiControl(c));
+	if (parent != NULL)
+		return uiDarwinControlChildrenShouldAllowSpaceAtTrailingEdge(uiDarwinControl(parent));
+	// always allow growth if not
+	return YES;
+}
+
+static BOOL uiGroupChildrenShouldAllowSpaceAtBottom(uiDarwinControl *c)
+{
+	uiControl *parent;
+
+	parent = uiControlParent(uiControl(c));
+	if (parent != NULL)
+		return uiDarwinControlChildrenShouldAllowSpaceAtBottom(uiDarwinControl(parent));
+	// always allow growth if not
+	return YES;
 }
 
 static void groupRelayout(uiGroup *g)
diff --git a/darwin/tab.m b/darwin/tab.m
index 8ceb7d4f..3138b890 100644
--- a/darwin/tab.m
+++ b/darwin/tab.m
@@ -56,9 +56,16 @@ uiDarwinControlDefaultSyncEnableState(uiTab, tabview)
 
 uiDarwinControlDefaultSetSuperview(uiTab, tabview)
 
-static void uiTabSetRealHuggingPriority(uiDarwinControl *c, NSLayoutPriority priority, NSLayoutConstraintOrientation orientation)
+static BOOL uiTabChildrenShouldAllowSpaceAtTrailingEdge(uiDarwinControl *c)
 {
-	// TODO
+	// always allow growth
+	return YES;
+}
+
+static BOOL uiTabChildrenShouldAllowSpaceAtBottom(uiDarwinControl *c)
+{
+	// always allow growth
+	return YES;
 }
 
 static void tabRelayout(uiTab *t)
diff --git a/darwin/window.m b/darwin/window.m
index 6c879ba4..4b2248f4 100644
--- a/darwin/window.m
+++ b/darwin/window.m
@@ -141,9 +141,16 @@ static void uiWindowSetSuperview(uiDarwinControl *c, NSView *superview)
 	// TODO
 }
 
-static void uiWindowSetRealHuggingPriority(uiDarwinControl *c, NSLayoutPriority priority, NSLayoutConstraintOrientation orientation)
+static BOOL uiWindowChildrenShouldAllowSpaceAtTrailingEdge(uiDarwinControl *c)
 {
-	// do nothing; uiWindow children never hug (to maintain parity with other OSs)
+	// always allow growth
+	return YES;
+}
+
+static BOOL uiWindowChildrenShouldAllowSpaceAtBottom(uiDarwinControl *c)
+{
+	// always allow growth
+	return YES;
 }
 
 static void windowRelayout(uiWindow *w)