[El Sanchez]

добавить кнопку "свернуть" в заголовок формы ( BorderStyle := bsDialog ) »

Johny777, так пойдет?

Код:

const
    GWL_STYLE = (-16);
    WS_MINIMIZEBOX = $20000;
    
function GetWindowLong(hWnd: HWND; nIndex: Integer): Longint; external 'GetWindowLongA@user32.dll stdcall';
function SetWindowLong(hWnd: HWND; nIndex: Integer; dwNewLong: Longint): Longint; external 'SetWindowLongA@user32.dll stdcall';

procedure InitializeWizard();
begin
    WizardForm.BorderStyle := bsDialog;
    SetWindowLong(WizardForm.Handle, GWL_STYLE, GetWindowLong(WizardForm.Handle, GWL_STYLE) or WS_MINIMIZEBOX);
end;