diff --git a/container_darwin.m b/container_darwin.m
index be49659e..485298e8 100644
--- a/container_darwin.m
+++ b/container_darwin.m
@@ -16,7 +16,7 @@ uiLogObjCClassAllocations
 
 - (void)viewDidMoveToSuperview
 {
-	if ([self superview] == nil)
+	if ([self superview] == destroyedControlsView)
 		if (self.uiChild != NULL) {
 			uiControlDestroy(self.uiChild);
 			self.uiChild = NULL;
diff --git a/tab_darwin.m b/tab_darwin.m
index deea075a..4e835b35 100644
--- a/tab_darwin.m
+++ b/tab_darwin.m
@@ -1,7 +1,9 @@
 // 12 april 2015
 #import "uipriv_darwin.h"
 
-// TODO very margins against extra space around the tab
+// TODO
+// - verify margins against extra space around the tab
+// - free child containers properly
 
 @interface uiNSTabView : NSTabView
 @property uiControl *uiC;
diff --git a/window_darwin.m b/window_darwin.m
index 539b113c..39027b14 100644
--- a/window_darwin.m
+++ b/window_darwin.m
@@ -1,6 +1,9 @@
 // 6 april 2015
 #import "uipriv_darwin.h"
 
+// TODO
+// - free chilld containers properly
+
 @interface uiWindowDelegate : NSObject <NSWindowDelegate>
 @property (assign) NSWindow *w;
 @property (assign) uiContainer *container;