selenium - waitfortext not working

[Nickleus]

here's my test in plain words:
* i have a table of users. 1 user on each row. at the end of each row there are two buttons: Edit | Remove
* click the Remove button (it has an id called remove_testbruker1)
* when i click the Remove button, a span next to it, containing the text Delete testbruker1?, with buttons Yes | No, will be made visible using css
* click Yes to delete the user
* check to see that the username is no longer present on the page (it has been deleted)

i was using code like this:

...
<tr>
    <td>click</td>
    <td>id=remove_testbruker1</td>
    <td></td>
</tr>
<tr>
    <td>waitForText</td>
    <td>Yes</td>
    <td></td>
</tr>
<tr>
    <td>clickAndWait</td>
    <td>Yes</td>
    <td></td>
</tr>
<tr>
    <td>assertTextNotPresent</td>
    <td></td>
    <td>testbruker1</td>
</tr>
...

i don't know why, but selenium wasn't finding the Yes button. the assertTextNotPresent also wasn't working, even though i finally got the Yes button to finally fire (see below), selenium still saw the username on the page, and i *think* i know why, i have a hunch that it was because i was using clickAndWait right before it and because the delete call is an ajax call so there is no page refresh (someone please correct me if i'm wrong), so after 2 rewrites i came up with this code:

<tr>
    <td>click</td>
    <td>id=remove_testbruker1</td>
    <td></td>
</tr>
<tr>
    <td>click</td>
    <td>//input[@value='Yes' and @type='button' and @onclick=&quot;document.getElementById('confirmBoxtestbruker1').style.visibility='hidden';this.form.submit();&quot;]</td>
    <td></td>
</tr>
<tr>
    <td>waitForTextNotPresent</td>
    <td>testbruker1</td>
    <td></td>
</tr>

and it worked. the //input ... is the xpath to the Yes button inside the span.
(see attachment: Endre == Edit, Fjern == Remove, Ja == Yes, Nei == No)