private void _helpButton_Click(object sender, EventArgs e)
{
if (_tab.SelectedTab == tabPage1)
HelpLauncher.Show(this, "Tasks/Basic_tasks/Change_languages.htm");
else if (_tab.SelectedTab == tabPage2)
HelpLauncher.Show(this, "Tasks/Basic_tasks/Select_front_matter_or_back_matter_from_a_pack.htm");
else if (_tab.SelectedTab == tabPage3)
HelpLauncher.Show(this, "Tasks/Basic_tasks/Enter_project_information.htm");
else
HelpLauncher.Show(this, "User_Interface/Dialog_boxes/Settings_dialog_box.htm");
}