diff --git a/Doc/graph/mask-classes.gv b/Doc/graph/mask-classes.gv
index 92e39c7368b69b9c539114f3382857124f304826..e573c05aefbea14fe789fc0337d17827db4674d5 100644
--- a/Doc/graph/mask-classes.gv
+++ b/Doc/graph/mask-classes.gv
@@ -3,6 +3,8 @@
 
 digraph maskClasses
 {
+size="8.1,11.5";
+
 node [shape=box];
 MaskEditingFrame -> MaskEditorActions;
 MaskEditingFrame -> MaskPanel;