I create a uniTreeMenu,with many subitems,when the subitems come out,the window do not have scroll bar, It should have. void __fastcall TMainForm::UniBitBtn1Click(TObject *Sender) { TUniTreeNode * pos; int i,j; for(int i=1;i<5;i++)     {     pos=UniTreeMenu1->Items->Add(NULL,"mainMenu_"+String(i));     for(int j=1;j<20;j++)         {         UniTreeMenu1->Items->Add(pos,"subMenu_"+String(j));         }     } }