::GetDialogFrame

To get the button frame for the wizard dialog and add a button to it:

namespace eval ::my_wizard {
    variable p_dlg ""
}

proc ::my_wizard::Run {} {
    set mangle [::model::GetMangle my_wizard_Run]
    variable p_dlg

    set p_dlg [::model::mdlWizardDlg wiz$mangle -width 400 -height 400 \
        -title "My Wizard" -showExport false -callback "::my_wizard::OnClose"]
    
    set frm [::model::mdlWizardDlg::GetButtonFrame $p_dlg]
    ::model::mdlWizardDlg::AddButtonToActionFrame $frm btnShow 4 "Show" ::my_wizard::OnShowButton

    ::model::mdlWizardDlg::ShowDialog
}

proc ::my_wizard::OnShowButton {} {
    set frm [::model::mdlWizardDlg::GetDialogFrame]
    if { [$frm cget -bg] == "red" } {
            $frm config -bg blue
      } else {
            $frm config -bg red
      }
}

proc ::my_wizard::OnClose { args } {
    variable p_dlg
    hwt::UnpostWindow $p_dlg
    return 1
}

::my_wizard::Run