diff --git a/src/calibre/gui2/convert/xexp_edit.ui b/src/calibre/gui2/convert/xexp_edit.ui
index 18b7c39b52..68c0c8c98e 100644
--- a/src/calibre/gui2/convert/xexp_edit.ui
+++ b/src/calibre/gui2/convert/xexp_edit.ui
@@ -43,6 +43,9 @@
          <height>0</height>
         </size>
        </property>
+       <property name="sizeAdjustPolicy">
+        <enum>QComboBox::AdjustToMinimumContentsLengthWithIcon</enum>
+       </property>
        <property name="minimumContentsLength">
         <number>30</number>
        </property>