Hello - hope someone can help me.

I am using data validation to allow the user to select from a drop-down list in a worksheet. I want them to only be able to select from the list and not to input any other values, and I have checked the box in Error message which says 'Show error alert after invalid data is entered' but I am still able to type in an invalid value without the error message appearing.

The named range which informs the list is large and includes lots of blank cells to enable me to add extra values to the list without having to rename the range, could this be the problem?