The Lookup field value is empty when you select the None value after you upload a document in SharePoint Server 2007

Consider the following scenario:

• You have a column in a custom list that has 19 items or more on a Microsoft Office SharePoint Server 2007 site.
• You add this column in the custom list to a document library as a lookup field.
• You select the None value for the lookup field after you upload a document to the document library.

In this scenario, the None value is empty. Also, to select items in the combo box, you have to double-click them instead of single-clicking them.

This issue occurs because it is tedious to look up items in a combo box that contains a long list. The control lets you type the value of the list item that you want to look up. The control automatically preselects in the list as you type.

To work around this issue, type the value of the list item that you want to look up.

This behavior is by design.