diff --git a/trytond/ir/ui/graph.rnc b/trytond/ir/ui/graph.rnc
index bf0f7f2713..2d19297a78 100644
--- a/trytond/ir/ui/graph.rnc
+++ b/trytond/ir/ui/graph.rnc
@@ -24,6 +24,7 @@ attlist.field &= attribute fill { "0" | "1" }?
 attlist.field &= attribute empty { "0" | "1" }?
 attlist.field &= attribute color { text }?
 attlist.field &= attribute widget { "float_time" }?
+attlist.field &= attribute float_time { text }?
 data = element data { attlist.data, xpath+ }
 attlist.data &= empty
 xpath = element xpath { attlist.xpath,
diff --git a/trytond/ir/ui/graph.rng b/trytond/ir/ui/graph.rng
index 4b1e6070ed..71cdb68961 100644
--- a/trytond/ir/ui/graph.rng
+++ b/trytond/ir/ui/graph.rng
@@ -120,6 +120,11 @@
       </attribute>
     </optional>
   </define>
+  <define name="attlist.field" combine="interleave">
+    <optional>
+      <attribute name="float_time"/>
+    </optional>
+  </define>
   <define name="data">
     <element name="data">
       <ref name="attlist.data"/>