I've been playing with the Cascading Combo boxes on my beta machine since they showed up about a month ago and they're very nice as shown in this video.

As Richard said, this is still a first release. There is some functionality that may throw errors upon moving to a different record, especially in continuous or datasheet forms. For the average user just enjoying the functionality of not needing VBA, it works great, however, if you are checking values in a cascading combo upon entry to a new record, specifically a value in a certain column, you may see an "Invalid Use of Null" error.

This doesn't appear to happen if you're only checking the value of the combo, just if you look at a specific column.

In the case I was testing, it was a form for entering line items on a voucher with 3 combos. It would check the value of a specific column of one of the combos and then mark certain fields has either "Enabled=No;Locked=Yes" or vice versa depending on the value of that column. However the Invalid Use of Null error would pop up in a continuous form when you moved to a row other than the row that initially loaded when the form opened.

For now, the workaround is simply to requery that combo before checking the value of the column and then it works fine.

Since this is still in development, it's not a big issue in my case but wanted to share if anyone runs into it.