[GRID] Get rid of [+] sign when using sub_row_ajax

When using sub_row_ajax, a small image of [+] sign is visible in column. It is all right, however I do use row-click to expand rows, therefore I would like to get rid of this column not to confuse users and save space. Is there any method to accomplish this?

The only way to made such update - modify code of sub_row excell

dhtmlxgrid_excell_sub_row.js   , line 10

this._setState = function(m,v){
        (v||this.cell).innerHTML="";

can be changed to
this._setState = function(m,v){
        (v||this.cell).innerHTML="

 
";