diff --git a/src/glade/editeventref.glade b/src/glade/editeventref.glade
index 7e984e57d..c5d3e6044 100644
--- a/src/glade/editeventref.glade
+++ b/src/glade/editeventref.glade
@@ -320,6 +320,7 @@
                       <object class="UndoableEntry" id="gid">
                         <property name="visible">True</property>
                         <property name="can_focus">True</property>
+                        <property name="tooltip_text" translatable="yes">A unique ID to identify the event</property>
                         <property name="invisible_char">●</property>
                       </object>
                       <packing>