diff --git a/trytond/ir/ui/board.rnc b/trytond/ir/ui/board.rnc
index 06662802c0..19fd9c112a 100644
--- a/trytond/ir/ui/board.rnc
+++ b/trytond/ir/ui/board.rnc
@@ -144,5 +144,6 @@ attlist.xpath &=
   attribute position { "inside" | "replace" | "replace_attributes" | "after" | "before" }?
 action = element action { attlist.action, empty }
 attlist.action &= attribute name { text }
+attlist.action &= [ a:defaultValue = "1" ] attribute colspan { text }?
 label |= notAllowed
 start = data | board | label
diff --git a/trytond/ir/ui/board.rng b/trytond/ir/ui/board.rng
index a0c90e3b8d..06d68504d2 100644
--- a/trytond/ir/ui/board.rng
+++ b/trytond/ir/ui/board.rng
@@ -447,6 +447,11 @@
   <define name="attlist.action" combine="interleave">
     <attribute name="name"/>
   </define>
+  <define name="attlist.action" combine="interleave">
+    <optional>
+      <attribute name="colspan" a:defaultValue="1"/>
+    </optional>
+  </define>
   <define name="label" combine="choice">
     <notAllowed/>
   </define>