diff --git a/qglengine/glscene.cpp b/qglengine/glscene.cpp
index 4b1b0b8..89fea9e 100644
--- a/qglengine/glscene.cpp
+++ b/qglengine/glscene.cpp
@@ -433,7 +433,7 @@ bool Scene::prepare() {
 	changed_materials.clear();
 	foreach (Material * m, materials) {
 		if (m->_changed) {
-			need_reload_materials = true;
+			need_reload_materials = tree_changed = true;
 			changed_materials << m;
 		}
 	}