diff --git a/lcl/comctrls.pp b/lcl/comctrls.pp
index 7955f08702..4e7a4f24a3 100644
--- a/lcl/comctrls.pp
+++ b/lcl/comctrls.pp
@@ -527,6 +527,7 @@ type
     property PageControl: TPageControl read GetPageControl write SetPageControl;
     property TabIndex: Integer read GetTabIndex;
   published
+    property AutoSize;
     property BorderWidth;
     property BiDiMode;
     property Caption;
@@ -606,6 +607,7 @@ type
     
     property Align;
     property Anchors;
+    property AutoSize;
     property BorderSpacing;
     property BiDiMode;
     property Constraints;
diff --git a/lcl/include/custompage.inc b/lcl/include/custompage.inc
index 1c2b5fec3c..000b40be77 100644
--- a/lcl/include/custompage.inc
+++ b/lcl/include/custompage.inc
@@ -221,6 +221,10 @@ end;
 
 function TCustomPage.IsControlVisible: Boolean;
 begin
+  // when autosizing, need this to return True so that the sizes of non-active
+  // pages will be considered in parent's GetPreferredSize()
+  if AutoSizingAll then
+    Exit(True);
   Result := inherited IsControlVisible;
   if Result and (Parent is TCustomTabControl) then
     Result := PageIndex = TCustomTabControl(Parent).PageIndex;