Maintain Focus on a Text Field inside a Table when validation fails

I would be highly grateful if someone could assist me with the following problem I am having. I have a multiple line text field in a table cell and when validation on it fails it should maintain focus on the field. I have used the following code posted on the forum which works fine when a text field is not placed within a table, however it does not seem to work when the text field is in a table cell.

Code placed in the validate event:

this.tst = this.rawValue > TextField1.rawValue;
this.tst || Boolean(this.execEvent("exit"));

Code placed in the exit event:

if(!(this.tst))
xfa.host.setFocus(this.somExpression);

Thanks in advance