What do these designer textbox properties do?

[tdk88]

When in Screen Designer, if you right-click a textbox and select Properties, you get the option of checking and unchecking several checkbox options.

I know what most of these do, except for a couple.

What do "Values from database" and "User definable" do? Both are unchecked by default.

Thanks.

 

[rsymonds]

In tech school they taught us if it ain't broke don't fix it.