Tied everything together. Now to fix build issues.

new/container_unix.c

@@ -34,8 +34,12 @@ static void uiContainer_remove(GtkContainer *container, GtkWidget *widget)
 
 static void uiContainer_size_allocate(GtkWidget *widget, GtkAllocation *allocation)
 {
+	uiControl *c;
+	uiSizing d;
+
 	gtk_widget_set_allocation(widget, allocation);
-	// TODO resize child
+	c = uiContainer(widget)->child;
+	(*(c->resize))(widget, allocation.x, allocation.y, allocation.width, allocation.height, &d);
 }
 
 struct forall {

new/main_unix.c

@@ -12,3 +12,9 @@ void uiQuit(void)
 {
 	gtk_main_quit();
 }
+
+// TODO move somewhere else
+uintptr_t uiControlHandle(uiControl *c)
+{
+	return (*(c->handle))(c);
+}

new/uipriv_unix.h

@@ -18,7 +18,9 @@ typedef struct uiContainer uiContainer;
 typedef struct uiContainerClass uiContainerClass;
 struct uiContainer {
 	GtkContainer parent_instance;
-	// TODO
+	// this is what triggers the resizing of all the children
+	uiControl *child;
+	// these are the actual children widgets of the container as far as GTK+ is concerned
 	GPtrArray *children;		// for forall()
 };
 struct uiContainerClass {

new/window_unix.c

@@ -3,6 +3,7 @@
 
 struct uiWindow {
 	GtkWidget *widget;
+	GtkWidget *container;
 	int (*onClosing)(uiWindow *, void *);
 	void *onClosingData;
 };
@@ -15,6 +16,8 @@ uiWindow *uiNewWindow(char *title, int width, int height)
 	w->widget = gtk_window_new(GTK_WINDOW_TOPLEVEL);
 	gtk_window_set_title(GTK_WINDOW(w->widget), title);
 	gtk_window_resize(GTK_WINDOW(w->widget), width, height);
+	w->container = newContainer();
+	gtk_container_add(GTK_CONTAINER(w->widget), w->container);
 	return w;
 }
 
@@ -58,3 +61,9 @@ void uiWindowOnClosing(uiWindow *w, int (*f)(uiWindow *, void *), void *data)
 	w->onClosingData = data;
 	g_signal_connect(w->widget, "delete-event", G_CALLBACK(onClosing), w);
 }
+
+void uiWindowSetChild(uiWindow *w, uiControl *c)
+{
+	uiContainer(w->container)->child = c;
+	(*(c->setParent))(c, (uintptr_t) (w->container));
+}