diff --git a/lcl/interfaces/lcl.lpk b/lcl/interfaces/lcl.lpk
index 4cefdc3e93..311cf4107e 100644
--- a/lcl/interfaces/lcl.lpk
+++ b/lcl/interfaces/lcl.lpk
@@ -131,7 +131,7 @@ end;"/>
     <License Value="modified LGPL-2
 "/>
     <Version Major="4" Minor="99"/>
-    <Files Count="555">
+    <Files Count="556">
       <Item1>
         <Filename Value="carbon/agl.pp"/>
         <AddToUsesPkgSection Value="False"/>
@@ -2734,6 +2734,11 @@ end;"/>
         <Filename Value="gtk3/gtk3lclnotebook.inc"/>
         <Type Value="Include"/>
       </Item555>
+      <Item556>
+        <Filename Value="gtk3/gtk3boxes.pas"/>
+        <AddToUsesPkgSection Value="False"/>
+        <UnitName Value="Gtk3Boxes"/>
+      </Item556>
     </Files>
     <CompatibilityMode Value="True"/>
     <LazDoc Paths="../../docs/xml/lcl"/>