I seek this solution.

Thank you for your help.

I researched and found some code defined by Tony for disabling the subgrid "+" buttons for rows who's subgrids are empty.

 {name:'ChildRecords',   hidden:true, sortable:false, editable:false,
  ],

        url:    'php/customertab-script.php',
        editurl:'php/customertab-script.php',
        mtype: 'POST',
        datatype: 'json',

        afterInsertRow: function(rowid, rowdata,rowelem) {if(parseInt(rowdata.ChildRecords,10) === 0){$('#'+rowid+' td.sgcollapsed','#tab4-grid').unbind('click').html('');}},

It works but when you click on the disabled area where the "+" button used to be, the "+" button comes back and still allows me to open an empty subgrid.

Tony also had another example that does not require a "ChildRecords" field:

afterInsertRow: function(rowid,rowdata,rowelem) {$('#'+rowid+' td').eq(0).unbind('click').html('');},

but i couldn't get that one to work correctly either.

I don't mind if i can still click on the hidden "+" button area and open empty subgrids.  What , I'd like for the hidden "+" button to stay hidden.  Is there a way to fix this?