diff --git a/src/common/treebase.cpp b/src/common/treebase.cpp
index 7b42fdd35e..a365ffc8b6 100644
--- a/src/common/treebase.cpp
+++ b/src/common/treebase.cpp
@@ -120,6 +120,8 @@ wxSize wxTreeCtrlBase::DoGetBestSize() const
     // need some minimal size even for empty tree
     if ( !size.x || !size.y )
         size = wxControl::DoGetBestSize();
+    else
+        CacheBestSize(size);
 
     return size;
 }