Bug fix: Tab order on extension options dialog was broken, if the extension mixed options in and out of group box.

(cherry picked from commit ac5d973a5ab741b4a7bd0cd99496cc155d18a359)

Source commit: ac3f3d1a021eb8c293f2fe1f060e19eaa7d97d5f

source/forms/Custom.cpp

@@ -346,6 +346,8 @@ void __fastcall TCustomDialog::StartGroup(const UnicodeString & Caption)
 
   AdjustHeight(GroupBox);
 
+  AddWinControl(GroupBox);
+
   FPos = ScaleByTextHeight(this, 16);
   FPrePos = FPos;
   FIndent = FHorizontalMargin;