Try adding this code to your form class:
#include <Windows.h>
. . .
private:
const int cGrip = 16;
const int cCaption = 32;
protected:
void WndProc( Message% m ) override
{
switch( m.Msg )
{
case WM_NCHITTEST:
Point pos = Point( m.LParam.ToInt32( ) );
pos = PointToClient( pos );
if( pos.Y < cCaption )
{
m.Result = IntPtr( HTCAPTION );
return;
}
if( pos.X >= ClientSize.Width - cGrip && pos.Y >= ClientSize.Height - cGrip )
{
m.Result = IntPtr( HTBOTTOMRIGHT );
return;
}
break;
}
__super::WndProc( m );
}
. . .