Index: lcl/extdlgs.pas
===================================================================
--- lcl/extdlgs.pas	(revision 63925)
+++ lcl/extdlgs.pas	(working copy)
@@ -51,6 +51,7 @@
   TPreviewFileDialog = class(TOpenDialog)
   private
     FPreviewFileControl: TPreviewFileControl;
+    function GetPreviewFileControl:TPreviewFileControl;
   protected
     class procedure WSRegisterClass; override;
     procedure CreatePreviewControl; virtual;
@@ -58,7 +59,7 @@
     function DoExecute: boolean; override;
   public
     constructor Create(TheOwner: TComponent); override;
-    property PreviewFileControl: TPreviewFileControl read FPreviewFileControl;
+    property PreviewFileControl: TPreviewFileControl read GetPreviewFileControl;
   end;
 
   { TOpenPictureDialog }
@@ -279,6 +280,13 @@
 
 { TPreviewFileDialog }
 
+function TPreviewFileDialog.GetPreviewFileControl: TPreviewFileControl;
+begin
+  if not Assigned(fPreviewFileControl) then
+    Self.CreatePreviewControl;
+  Result:=fPreviewFileControl;
+end;
+
 class procedure TPreviewFileDialog.WSRegisterClass;
 begin
   inherited WSRegisterClass;