Sorry. I'm a bit rusty with javascript.
So, I added it to the array.
If I remove the trigger <asp:AsyncPostBackTrigger ControlID="SearchBoxx" EventName="TextChanged" /> from the <triggers> in aspx, the array size decreases to 0, and is 1 after I add the 'SearchBox' HTML control to it. It still does not work, because it now refreshes the whole page again. There is something missing to this story. Something to tell the pagerequest manager to only update the updatepanel? The markup generated for the textboxes is identical in both cases. The only difference on the page is this:
Sys.WebForms.PageRequestManager.getInstance()._updateControls(['tUpdatePanel1'], ['SearchBoxx'], [], 90);
When there is no <trigger> present, the second parameter is empty. And I tried to add that to a script at the end of the ASPX file, but it still refreshes the whole page....
Aaaaa. I would really like to get rid of the asp:TextBox control, as it is doing nothing on the page...
Miha