Steps to reproduce
1. Create a test impersonating any user (administrator or a user with certain limitations).
2. Add a test step 'Open a Catalog Item' and add any Catalog Item with a Mandatory List collector field.
3. Add a test step 'Set Variable Values' and fill the List collector field with a value that is certain to be found.
4. Add a test step 'Order Catalog Item'.
5. Run the test. The catalog item is not ordered with values selected in the List collector field. To ensure this, the field in question can be made mandatory. This way the test will fail.
Resolution
The workaround is to add a variable attribute "glide_list" to your List collector variable.
Additional Information
If you are running a version previous the London release, you may encounter the known problem below:
PRB1188106/KB0692088 - UI Policies can not build conditions on a list collector variable with attribute set to 'glide_list'. The reference list look up window does not open to select a value.