Changing the size multiselect text box

We had multiselect where the users would pick the week which is in the format FY2009-Q3-MAR-W3. The multiselect are size of 10. So in the textbox complete string couldn't be seen, as in image.

The user wanted to see the complete string of one selected string. OBIEE didn't have any options of increasing the width. As a round about this is what I did.
1. I copied the promptviewtemplates.xml from {OracleBI}\web\msgdb\messages to {OracleBIData}\web\msgdb\customMessages folder.
2. I searched for the below tag in the above copied the xml file.

3. Changed the size value to size="16".
4. Restarted the presentation services.
The sizes of the prompts were changed as below.