diff --git a/system.go b/system.go
index c1fb1db..9da1094 100644
--- a/system.go
+++ b/system.go
@@ -241,7 +241,9 @@ func (window *window) afterEvent () {
 		// set child bounds
 		childBounds := window.metrics.bounds
 		childBounds = childBounds.Sub(childBounds.Min)
-		window.root.SetBounds(childBounds)
+		if window.root != nil {
+			window.root.SetBounds(childBounds)	
+		}
 
 		// full relayout/redraw
 		if window.root != nil {