Multiple instances fail being escapable

[dy]

If we create multiple dialogs:

var a = Dialog('a').escapable();
var b = Dialog('b').escapable();
var c = Dialog('c').escapable();
b.show();

then b will not be closed by escape. That is because of that string. active there is not the initial dialog anymore, as far other dialogs have overwritten it. Not sure what is the purpose of active, it seems that it is better to use self.