You can also try:
Names Default to Here( 1 );
keepopen = 0;
New Window( "Example", Show Menu( 0 ), Show Toolbars( 0 ), Suppress Autohide,
<<Modal, <<On Validate(!keepopen),
Text Box( "Example: Keep Dialog Open Checkbox" ),
Text Box( "" ),
H List Box(
keepcbox = Check Box( "Keep dialog open", keepopen = keepcbox << get( 1 ) ),
Button Box( "OK",
// Insert name of an expression to run as a script
),
Button Box( "Cancel")
)
);
<<On Validate(expression), runs the expression when the OK button is hit. If the expression returns 1 then it will close the window. This has the benefit of allowing Cancel and X buttons to actually close the window, but prevents OK button from doing so.