OK
1. Leave the Hint property blank
2. UniDBGrid -> ClientEvents -> ExtEvents -> function reconfigure(sender, store, columns, oldStore, oldColumns, eOpts):
function reconfigure(sender, store, columns, oldStore, oldColumns, eOpts)
{
//for example actioncolumnIndx = 6, actionButtonIndx = 0, recordDataIndx = 0
columns[6].items[0].getTip = function(value, metadata, record, row, col, store) {
return record.data[0] > 1500 ? 'Hint1' : 'Hint2';
}
}