Add html:div to get buttons working

xpfe/components/ucth/resources/unknownContent.xul

@@ -89,6 +89,8 @@
 
     </html:script>
 
+    <html:div flex="100%">
+
     <html:table style="width:100%;">
         <html:tr>
             <html:td colspan="4">
@@ -115,4 +117,6 @@
         </html:tr>
     </html:table>
 
+    </html:div>
+
 </window>