Focus function not working without alert

[joboy]

This JS code is on RoR+ImgMap site.

I've tweak several portion of ImgMap, specifically around line 2205 of the file imgmap.js by adding this code

$$('#img_area_'+this.currentid.toString()+' .img_href').first().focus();
alert('Click here');

as replacement to..

this.addNewArea();

so that when the user draws a shape, the focus will be set to the respective href field, instead of the default behavior - adding new row(imgmap form).

but for brevity let me just simply the code..

$('elem_id').focus();
alert('Click here');

If i'll removed alert function, focus() won't do its job.

Alert is really disturbing.. can anyone explain why this is happening?

Thanks.