Vertical header is invisible.

diff --git a/ui/mainwindow.ui b/ui/mainwindow.ui
index f89bdf1..c1f3a62 100644
--- a/ui/mainwindow.ui
+++ b/ui/mainwindow.ui
@@ -41,6 +41,9 @@
         <attribute name="horizontalHeaderVisible">
          <bool>false</bool>
         </attribute>
+        <attribute name="verticalHeaderVisible">
+         <bool>false</bool>
+        </attribute>
         <attribute name="verticalHeaderStretchLastSection">
          <bool>false</bool>
         </attribute>