How to increase number of items shown in multiple list

Hi,
I have a custom field with "list" type and the "multiple" option checked.
There are more than 50 items in the definition list.

When I have to use it, in a new issue for example, it only shows 4 items, and I have to scroll to see others (more than 46 others...).
It is not easy to see which you have already selected and those you want to select.

Is there a way to change the number of shown items or the height of the text area ?