well first off when dynamicly creating the kodak thing just do this frame->GetWindowRect(&rect); kodak->MoveWindow(&rect); that way you ensure the kodak is the the same size as the frame on creation you may want to adjust the size slightly its up to you you could either inherate the frame class and overload its OnLButtonClk message or just use your windows message and use GetCursorPos and just test if its within the frame window and around the permiter then on the OnMouseMove do some work while the user is trying to resize thier thing and then finaly do your resizing in OnLButtonUp also you can do this without the frame and just use the kodak thing where you would use the frame although i think the frame gives your control something easier to stick to also if you didnt know you can get your kodak control in functions were its not in scope by doing GetDlgItem(ID_KODAK) same with the frame control