Description of problem:
The list should just be a simple drop-down list.  It has a fixed list of choices and that list is unlikely to have enough entries to make autocompletion worthwhile.

The current behaviour misleads the user into thinking they can type a new value that isn't in the list, but such values get cleared as soon as the focus moves to a different widget.

Version-Release number of selected component (if applicable):
5.0.3

How reproducible:
Always

Steps to Reproduce:
1. Select New->Red Hat->Red Hat Enterprise Linux 7
2. Type "Bugzilla" into the Dependent Products widget
3. Click Submit

Actual results:
The value entered into the Dependent Products field vanishes and the bug is submitted without it.

Expected results:
Either:
- The user can enter customer values into the field and have them saved successfully, or
- The user is given a fixed list of values and cannot enter any other values.

Additional info:
none