The following example shows all hidden folders in gray. Don't forgert to set the ShowHidden property to True.
procedure TMainForm.ShellTreeAddFolder(Node: TJamShellTreeNode; path: string; var CanAdd: Boolean); begin try if (FileGetAttr(Node.FullPath) and FILE_ATTRIBUTE_HIDDEN) > 0 then Node.TextColor := clDkGray; except on EDirectoryNotFoundException do exit; end; end;