Active X Combo Box - non-matching fields

[kitkat2]

Hi all,

I currently have an ActiveX Combo Box set up with a dropdown list of values.

I previously had these set up via Data Validation as normal dropdown lists, however, switched to Combo Boxes to allow the predictive text feature to be enabled.

Now, I am wondering if it's possible to do one of the following:

1. One of the values in the dropdown list via the combo box is "other". If "other" is selected, the user should be prompted to input an ad hoc value (unsure if this can be done via a dialogue box?)

OR

2. If the User types in a value which doesn't match an existing value from the list, they can save their entry by clicking Tabbing or Entering into the next cell.

Any ideas? Help much appreciated

Thanks

Kat