How to avoid error when using the row change handler?
go_down_expr = Expr(
cur_row = (dt << get selected rows());
If(
N Items( cur_row ) == 0,
New Window( "Alert", <<size( 300, 100 ), Border Box( top( 10 ), bottom( 10 ), Left( 10 ), Right( 10 ), Text Box( "No selection" ) ) ),
N Items( Loc( crows > cur_row[1] ) ) == 0, dt << gotorow( crows[1] ),
dt << go to row( crows[(Loc( crows > cur_row[1] ))[1]] )
);
);
f = Function( {a = [1]},
...