thanks for responding,
The dataSource is not readOnly and the datasource is not EOF. The problem is very sporadic, sometimes they enable, sometines they do not. They are both one state or another and both have different data sources. In one cbo the items are added to the list programmitcally:

WITH thisform.clsdatadesc.cboGlAcctNum
    .Sorted = .T.
    .DisplayCount = 7
    .columnLines = .t.
    .ControlSource = "apInvPoItems.glAcctNum"
    .rowsourcetype = 2 && alias
    .rowsource = "glAccts.glAcctNum, glAcctName" 
    .columncount = 2
    .boundcolumn = 1
    .columnWidths = "50,165"
    .style = 2
ENDWITH

WITH thisform.clsdatadesc.cboFactor
    *** form.activate
    .AddItem("Discount")
       .List[.newindex,2] = "D"
    .AddItem("No Discount")
       .List[.newindex,2] = "N"
    .AddItem("Freight")
       .List[.newindex,2] = "F"
    .AddItem("Taxes")
       .List[.newindex,2] = "T"
    .sorted = .f.
    .controlSource = "apInvPoItems.factor"
    .boundcolumn = 2
    .columncount = 2
    .columnWidths = "80,10"
    .displayCount = 5
    .style = 2
    .enabled = .T.
    .listindex = 1
    .readonly = .F.
ENDWITH

Thanks again, any other suggestions appreciated.
Vince