diff --git a/darwin/box.m b/darwin/box.m
index c9e81380..270d9b08 100644
--- a/darwin/box.m
+++ b/darwin/box.m
@@ -72,9 +72,13 @@ struct uiBox {
 		// the weird names vert and bb are to shut the compiler up about shadowing because implicit this/self is stupid
 		self->b = bb;
 		self->vertical = vert;
+		self->padded = 0;
 		self->children = [NSMutableArray new];
 		self->nStretchy = 0;
 
+		self->inBetweens = [NSMutableArray new];
+		self->otherConstraints = [NSMutableArray new];
+
 		if (self->vertical) {
 			self->primaryStart = NSLayoutAttributeTop;
 			self->primaryEnd = NSLayoutAttributeBottom;