diff --git a/container_darwin.m b/container_darwin.m
index 747ccf7c..333b9143 100644
--- a/container_darwin.m
+++ b/container_darwin.m
@@ -23,12 +23,27 @@ uiLogObjCClassAllocations
 }
 
 - (void)setFrameSize:(NSSize)s
+{
+	[super setFrameSize:s];
+	[self uiUpdateNow];
+}
+
+- (void)uiUpdateNow
 {
 	uiSizing d;
 
-	[super setFrameSize:s];
 	if (self.child != NULL)
 		(*(self.child->resize))(self.child, [self bounds].origin.y, [self bounds].origin.y, [self bounds].size.width, [self bounds].size.height, &d);
 }
 
 @end
+
+void updateParent(uintptr_t parent)
+{
+	uiContainer *c;
+
+	if (parent == 0)
+		return;
+	c = (uiContainer *) parent;
+	[c uiUpdateNow];
+}
diff --git a/newcontrol_darwin.m b/newcontrol_darwin.m
index 04f6c1cb..8b0bd48b 100644
--- a/newcontrol_darwin.m
+++ b/newcontrol_darwin.m
@@ -8,6 +8,7 @@ struct uiSingleViewControl {
 	NSView *view;
 	NSScrollView *scrollView;
 	NSView *immediate;		// the control that is added to the parent container; either view or scrollView
+	uintptr_t parent;
 };
 
 #define S(c) ((uiSingleViewControl *) (c))
@@ -24,9 +25,17 @@ static uintptr_t singleHandle(uiControl *c)
 
 static void singleSetParent(uiControl *c, uintptr_t parent)
 {
-	NSView *parentView = (NSView *) parent;
+	uiSingleViewControl *s = S(c);
+	uintptr_t oldparent;
+	NSView *parentView;
 
-	[parentView addSubview:S(c)->immediate];
+	oldparent = s->parent;
+	s->parent = parent;
+	parentView = (NSView *) (s->parent);
+	// TODO will this change parents?
+	[parentView addSubview:s->immediate];
+	updateParent(oldparent);
+	updateParent(s->parent);
 }
 
 // also good for NSBox and NSProgressIndicator
diff --git a/uipriv_darwin.h b/uipriv_darwin.h
index 514297cb..1205d81b 100644
--- a/uipriv_darwin.h
+++ b/uipriv_darwin.h
@@ -36,5 +36,7 @@ extern void setStandardControlFont(NSControl *);
 
 // container_darwin.m
 @interface uiContainer : NSView
+// TODO rename to uiChild
 @property uiControl *child;
+- (void)uiUpdateNow;
 @end
diff --git a/window_darwin.m b/window_darwin.m
index 613b78f3..c2c312a1 100644
--- a/window_darwin.m
+++ b/window_darwin.m
@@ -1,9 +1,6 @@
 // 6 april 2015
 #import "uipriv_darwin.h"
 
-// TODO
-// - showing on size
-
 @interface uiWindowDelegate : NSObject <NSWindowDelegate>
 @property (assign) NSWindow *w;
 @property (assign) uiContainer *container;