[win32] - how make the form transparent?

[Cambalinho]

i have 1 function for make the form transparent:

void settransparency(HWND handlewindow,color backcolor, std::uint8_t Transperancy=255)
        {
            long wAttr = GetWindowLong(handlewindow, GWL_EXSTYLE);
            if(backcolor==-1)
            {
                SetWindowLong(handlewindow, GWL_EXSTYLE, wAttr | WS_EX_LAYERED);
                SetLayeredWindowAttributes(handlewindow, NULL, Transperancy, 0x02);
            }
            else
            {
                SetWindowLong(handlewindow, GWL_EXSTYLE, wAttr | WS_EX_LAYERED);
                SetLayeredWindowAttributes(handlewindow, backcolor, Transperancy, 0x02 | 0X01);
            }

        }

the form stays transparent, but i lose some actions :(
is there another way for make the form transparent?(just hide the backcolor)

[Cambalinho]

what a diference between transparent form and shaped form?
the transparent form is only for see(and not click) what is on back? and the shaped form can let us click on back?