You can use functions like `is control key()`, like this:
New Window("Modifier Key Check",
vlb = V List Box(
Mouse Box(
Graph Box(),
<<setClickEnable( 1 ),
<< Set Click(
Function( {this, clickpt, event},
if( event == "Pressed",
if( is alt key(),
txt = "pressed with alt",
is control key(),
txt = "pressed with control",
is shift key(),
txt = "pressed with shift",
txt = "pressed"
);
New Window("Button Pressed", << Modal, text box( txt ) );
)
)
)
)
)
);