Fixed height of the select element with multiple attribute.

[Issue tracking](http://joomlacode.org/gf/project/joomla/tracker/?action=TrackerItemEdit&tracker_id=8103&tracker_item_id=29424)

When you have multiple values attribute tyou expect that select will show you at least few values. And even when you set `size` attribute to your `<select>` element you expect it to how as many values as `size` sets.

In protstar template CSS set height to `28px` for amy multiple select elements with make then absolutely unusable.

Here is the select element before fix

![2013-05-09_15-08-51](https://f.cloud.github.com/assets/650741/482107/27d8d672-b888-11e2-97f2-a3277343a6a4.png)

and here is after fix

![2013-05-09_15-09-04](https://f.cloud.github.com/assets/650741/482108/32dd41f2-b888-11e2-9316-839639cb662e.png)