hide the AddNew button for some, but not all of the bands in UltraWebGrid

This is possible through some JavaScript code.

The Grid's add new buttons are given IDs as follows:
gridname+_+an+_+band number.

Example:
Grid name=UltraWebGrid1
band=1.
the button Id = UltraWebGrid1_an_1

Therefore, place the following JavaScript block AFTER the grid in the HTML, and your grid will no longer display the band 1 add new button:

place this code inside script tags:

igtbl_getElementById("UltraWebGrid1_an_1").style.display="none";