diff --git a/easygui/boxes/base_boxes.py b/easygui/boxes/base_boxes.py
index 7bc67d4..9e9595c 100644
--- a/easygui/boxes/base_boxes.py
+++ b/easygui/boxes/base_boxes.py
@@ -20,8 +20,10 @@ def bindArrows(widget):
 
 
 def tabRight(event):
-    boxRoot.event_generate("<Tab>")
+    if boxRoot:
+        boxRoot.event_generate("<Tab>")
 
 
 def tabLeft(event):
-    boxRoot.event_generate("<Shift-Tab>")
+    if boxRoot:
+        boxRoot.event_generate("<Shift-Tab>")