diff --git a/redo/darwin/bin.m b/redo/darwin/bin.m
new file mode 100644
index 00000000..d2add788
--- /dev/null
+++ b/redo/darwin/bin.m
@@ -0,0 +1,69 @@
+// 28 april 2015
+#import "uipriv_darwin.h"
+
+// This is a uiControl wrapper a la GtkBin on GTK+.
+// It serves the function of tabPage on Windows: it allows uiWindow and uiTab to give their children a real uiControl as a parent while not screwing with the internal NSView structure of those uiControls.
+// It also provides margins.
+
+struct bin {
+	uiControl c;
+	NSView *view;
+	uiControl *child;
+	int margined;
+};
+
+uiDefineControlType(bin, binType, struct bin)
+
+static uintptr_t binHandle(uiControl *c)
+{
+	struct bin *b = (struct bin *) c;
+
+	return (uintptr_t) (b->view);
+}
+
+uiControl *newBin(void)
+{
+	struct bin *b;
+
+	b = (struct bin *) uiNewControl(binType());
+
+	// a simple NSView will do fine
+	b->view = [[NSView alloc] initWithFrame:NSZeroRect];
+	uiDarwinMakeSingleWidgetControl(uiControl(b), b->view, NO);
+
+	uiControl(b)->Handle = binHandle;
+
+	return uiControl(b);
+}
+
+void binSetChild(uiControl *c, uiControl *child)
+{
+	struct bin *b = (struct bin *) c;
+	NSView *childView;
+
+	if (b->child != NULL) {
+		childView = (NSView *) uiControlHandle(b->child);
+		[childView removeFromSuperview];
+	}
+	b->child = child;
+	if (b->child != NULL) {
+		uiControlSetParent(b->child, uiControl(b));
+		childView = (NSView *) uiControlHandle(b->child);
+		// TODO auto layout to autoresize
+	}
+}
+
+int binMargined(uiControl *c)
+{
+	struct bin *b = (struct bin *) c;
+
+	return b->margined;
+}
+
+void binSetMargined(uiControl *c, int margined)
+{
+	struct bin *b = (struct bin *) c;
+
+	b->margined = margined;
+	// TODO use auto layout
+}
diff --git a/redo/darwin/tab.m b/redo/darwin/tab.m
index dace0b60..68d96faf 100644
--- a/redo/darwin/tab.m
+++ b/redo/darwin/tab.m
@@ -24,10 +24,12 @@ static void tabCommitDestroy(uiControl *c)
 	// the above loop serves the purpose of binSetParent()
 	[t->pages enumerateObjectsUsingBlock:^(id obj, NSUInteger index, BOOL *stop) {
 		NSValue *v = (NSValue *) obj;
-		uiBin *p;
+		uiControl *bin;
 
-		p = (uiBin *) [v pointerValue];
-		uiControlDestroy(uiControl(p));
+		bin = (uiControl *) [v pointerValue];
+		binSetChild(bin, NULL);
+		// TODO destroy the child
+		uiControlDestroy(uiControl(bin));
 	}];
 	// and finally destroy ourselves
 	[t->pages release];
@@ -59,13 +61,14 @@ static void tabContainerUpdate(uiControl *c)
 	struct tab *t = (struct tab *) c;
 
 	(*(t->baseEnable))(uiControl(t));
+	// TODO enumerate over page CONTROLS instead
 	[t->pages enumerateObjectsUsingBlock:^(id obj, NSUInteger index, BOOL *stop) {
 		NSValue *v = (NSValue *) obj;
-		uiBin *page;
+		uiControl *bin;
 
-		page = (uiBin *) [v pointerValue];
+		bin = (uiControl *) [v pointerValue];
 		// TODO get the right function
-		uiContainerUpdate(uiControl(page));
+		uiContainerUpdate(uiControl(bin));
 	}];
 }
 
@@ -73,11 +76,11 @@ static void tabContainerUpdate(uiControl *c)
 static void tabAppend(uiTab *tt, const char *name, uiControl *child)
 {
 	struct tab *t = (struct tab *) tt;
-	uiBin *page;
+	uiControl *page;
 	NSTabViewItem *i;
 
 	page = newBin();
-	uiBinSetMainControl(page, child);
+	binSetChild(page, child);
 	[t->pages addObject:[NSValue valueWithPointer:page]];
 	[t->margined addObject:[NSNumber numberWithInt:0]];
 
@@ -90,11 +93,11 @@ static void tabAppend(uiTab *tt, const char *name, uiControl *child)
 static void tabInsertAt(uiTab *tt, const char *name, uintmax_t n, uiControl *child)
 {
 	struct tab *t = (struct tab *) tt;
-	uiBin *page;
+	uiControl *page;
 	NSTabViewItem *i;
 
 	page = newBin();
-	uiBinSetMainControl(page, child);
+	binSetChild(page, child);
 	[t->pages insertObject:[NSValue valueWithPointer:page] atIndex:n];
 	[t->margined insertObject:[NSNumber numberWithInt:0] atIndex:n];
 
@@ -108,7 +111,7 @@ static void tabDelete(uiTab *tt, uintmax_t n)
 {
 	struct tab *t = (struct tab *) tt;
 	NSValue *v;
-	uiBin *page;
+	uiControl *page;
 	NSTabViewItem *i;
 
 	v = (NSValue *) [t->pages objectAtIndex:n];
@@ -117,7 +120,7 @@ static void tabDelete(uiTab *tt, uintmax_t n)
 	[t->margined removeObjectAtIndex:n];
 
 	// make sure the children of the tab aren't destroyed
-	uiBinSetMainControl(page, NULL);
+	binSetChild(page, NULL);
 
 	// remove the bin from the tab view
 	// this serves the purpose of uiBinRemoveOSParent()
@@ -166,11 +169,12 @@ static void tabSetMargined(uiTab *tt, uintmax_t n, int margined)
 	[t->margined replaceObjectAtIndex:n withObject:v];
 	pagev = (NSValue *) [t->pages objectAtIndex:n];
 	page = (uiBin *) [pagev pointerValue];
+/* TODO
 	if ([v intValue])
 		uiBinSetMargins(page, tabLeftMargin, tabTopMargin, tabRightMargin, tabBottomMargin);
 	else
 		uiBinSetMargins(page, 0, 0, 0, 0);
-	uiContainerUpdate(uiContainer(page));
+*/
 }
 
 uiTab *uiNewTab(void)
diff --git a/redo/darwin/uipriv_darwin.h b/redo/darwin/uipriv_darwin.h
index 1857d95e..da25403b 100644
--- a/redo/darwin/uipriv_darwin.h
+++ b/redo/darwin/uipriv_darwin.h
@@ -56,5 +56,11 @@ extern uiWindow *windowFromNSWindow(NSWindow *);
 extern void initAlloc(void);
 extern void uninitAlloc(void);
 
+// bin.c
+extern uiControl *newBin(void);
+extern void binSetChild(uiControl *, uiControl *);
+extern int binMargined(uiControl *);
+extern void binSetMargined(uiControl *, int);
+
 // TODO
 #define PUT_CODE_HERE 0
diff --git a/redo/unix/tab.c b/redo/unix/tab.c
index 2a11df14..cb51243b 100644
--- a/redo/unix/tab.c
+++ b/redo/unix/tab.c
@@ -48,6 +48,8 @@ static uintptr_t tabHandle(uiControl *c)
 	return (uintptr_t) (t->widget);
 }
 
+// TODO tabContainerUpdate()?
+
 static void tabAppend(uiTab *tt, const char *name, uiControl *child)
 {
 	struct tab *t = (struct tab *) tt;