Thank you for reporting this. As a matter of fact, this is an issue with Internet Explorer only. If you use Mozilla Firefox, you will notice that there is no such problem. In Internet Explorer the issue could be solved with css by enlarging the width, but as you can see, if the combo is larger it will exceed the width of its parent.
I will talk to our webteam if they could do another thing - to strip the / Sitefinity Support Forums / string in the combo, as it is not needed.
In the meantime, for your convenience, you may use Mozilla Firexox.
Have a great weekend!
the Telerik team