diff --git a/darwin/box.m b/darwin/box.m
index 3e2eb3cf..c41ab6f1 100644
--- a/darwin/box.m
+++ b/darwin/box.m
@@ -94,6 +94,10 @@ struct uiBox {
 			self->primaryOrientation = NSLayoutConstraintOrientationHorizontal;
 			self->secondaryOrientation = NSLayoutConstraintOrientationVertical;
 		}
+
+		// TODO default high?
+		self->horzHuggingPri = NSLayoutPriorityRequired;
+		self->vertHuggingPri = NSLayoutPriorityRequired;
 	}
 	return self;
 }