Dojo attach point / byId returns undefined - dojo

Question

I made a template and there is a <select dojotype="dijit.form.ComboBox" dojoAttachPoint="selectPageNumber" id="selectPageNumber">tag with id and dojoAttachPoint be "selectPageNumber". I want to populate it with options upon create so I add some code to the postCreate function:
var select = dijit.byId("selectPageNumber");
or
var select = this.selectPageNumber;
but I always have select being undefined.
What am I doing wrong?
UPD:
The problem with element has been solved spontaneously and I didn't got the solution. I used neither dojo.addOnLoad nor widgetsInTemplate : true, it just started to work. But I have found the same problem again: when I added another tag I can't get it!
HTML:
<select class="ctrl2" dojotype="dijit.form.ComboBox" dojoAttachPoint="selectPageNumber" id="selectPageNumber">
</select>
<select class="ctrl2" dojotype="dijit.form.ComboBox" dojoAttachPoint="selectPageNumber2" id="selectPageNumber2">
</select>
widget:
alert(this.selectPageNumber);
alert(this.selectPageNumber2);
first alert shows that this.selectPageNumber is a valid object and the this.selectPageNumber2 is null.
widgetsInTemplate is set to false.
all the code is within dojo.addOnLoad()
dojo.require() is valid
I am using IBM Rational Application Developer (if it is essential).
WHY it is so different?

Answer 1

Based on your syntax, I am assuming that you are using 1.6. Your question mentions template and postCreate, so i am assuming that you have created a widget that acts as a composite (widgets in the template).
Assuming 1.6, in your widget, have you set the widgetsInTemplate property to true. This will tell the parser that your template has widgets that need to be parsed when creating the widget.
http://dojotoolkit.org/documentation/tutorials/1.6/templated/
I would remove the id from the select. Having the id means that you can only instantiate your widget once per page. You should use this.selectPageNumber within your widget to access the select widget.
If you are using 1.7 or greater, instead of setting the widgets widgetsInTemplate property, you should use the dijit._WidgetsInTemplateMixin mixin.
http://dojotoolkit.org/reference-guide/1.8/dijit/_WidgetsInTemplateMixin.html

Answer 2

Depending on when dijit.byId() is being called, the widget may not have been created yet. Try using dojo.addOnLoad()
dojo.addOnLoad(function() {
var select = dijit.byId("selectPageNumber");
});

Answer 3

I came close to the solution: it seems like there is a some sort of RAD "caching" that doesn't respond to changes made in html code.
Ways to purge the workspace environment with RAD (based on Eclipse) might be a solution.