Limit width on Bootstrap input-group - html

Question

I'm struggling with a problem for several days now and I couldn't find a solution yet, even though I've tried myself with different approaches, searched google and the mighty stackoverlow for hours.
The set-up:
I've got a panel with two list-groups next to each other, where relations can be managed. On the left are the linked items, on the right all available items that are not linked yet (featuring a pagination and all). The js-logic is working flawless. Clicking on a question-mark does display details for the item. Clicking on a plus moves an item to the left list, clicking on an "x" moves it back to the right. Of course the icons are properly switched, too.
The problem:
The items are user-generated and the form is used both on big and small screens (used bootstrap for that reason).
Some of the items do have a rather long name, limiting the users to keep it short is not an option here. If the text is too long, it just breaks out of the layout.
What I tried so far:
Since the input-groups work with simulating table-elements, I've tried several approaches with table-layout:fixed;, but that doesn't seem to work if it's not really a table. Then I tried several approaches with containing different elements in div-containers and giving them percentual sizes.
It never worked.
Now I'm experimenting with cutting the text server-side, but that looks stupid if the screen is wide enough and the text is cut anyway.
Does someone smarter than me have a solution that makes overflow:hidden; and text-overflow:ellipis; work on those elements?
Here is a (very cleaned-up) fiddle to work with:
https://jsfiddle.net/Fanmade/9vf8xvuL/
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<link href="https://maxcdn.bootstrapcdn.com/font-awesome/4.6.3/css/font-awesome.min.css" rel="stylesheet"/>
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css" rel="stylesheet"/>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js"></script>
<div class="panel panel-default">
<div class="panel-body">
<div class="row">
<div class="col-md-6">
<ul class="list-group" id="left">
<li class="list-group-item">
<h4 class="text-center">Header Left</h4>
</li>
<li class="list-group-item">
<div class="input-group">
<a href="#" class="btn input-group-addon info-button">
<i class="fa fa-question-circle-o fa-lg"></i>
</a>
<button class="btn btn-default form-control" type=button>
Element 1
</button>
<a href="#" class="btn switch btn-remove input-group-addon">
<i class="fa fa-times fa-lg"></i>
</a>
</div>
</li>
<li class="list-group-item">
<div class="input-group">
<a href="#" class="btn input-group-addon info-button">
<i class="fa fa-question-circle-o fa-lg"></i>
</a>
<button class="btn btn-default form-control" type=button>
Element 2
</button>
<a href="#" class="btn switch btn-remove input-group-addon">
<i class="fa fa-times fa-lg"></i>
</a>
</div>
</li>
<li class="list-group-item">
<div class="input-group">
<a href="#" class="btn input-group-addon info-button">
<i class="fa fa-question-circle-o fa-lg"></i>
</a>
<button class="btn btn-default form-control" type=button>
Element 3
</button>
<a href="#" class="btn switch btn-remove input-group-addon">
<i class="fa fa-times fa-lg"></i>
</a>
</div>
</li>
</ul>
</div>
<div class="col-md-6">
<ul class="list-group" id="left">
<li class="list-group-item">
<h4 class="text-center">Header Right</h4>
</li>
<li class="list-group-item">
<div class="input-group">
<a href="#" class="btn input-group-addon info-button">
<i class="fa fa-plus fa-lg"></i>
</a>
<button class="btn btn-default form-control" type=button>
Element 4
</button>
<a href="#" class="btn switch btn-remove input-group-addon">
<i class="fa fa-question-circle-o fa-lg"></i>
</a>
</div>
</li>
<li class="list-group-item">
<div class="input-group">
<a href="#" class="btn input-group-addon info-button">
<i class="fa fa-plus fa-lg"></i>
</a>
<button class="btn btn-default form-control" type=button>
Element 5 just has a really long text and I don't want to cut it when there is enough space on wide screens
</button>
<a href="#" class="btn switch btn-remove input-group-addon">
<i class="fa fa-question-circle-o fa-lg"></i>
</a>
</div>
</li>
<li class="list-group-item">
<div class="input-group">
<a href="#" class="btn input-group-addon info-button">
<i class="fa fa-plus fa-lg"></i>
</a>
<button class="btn btn-default form-control" type=button>
Element 6
</button>
<a href="#" class="btn switch btn-remove input-group-addon">
<i class="fa fa-question-circle-o fa-lg"></i>
</a>
</div>
</li>
</ul>
</div>
</div>
</div>
</div>
Edit after the answers:
Thank you both so much for the answer!
I'm feeling so stupid right now. Of course the answer had to be so simple and I was just searching in the wrong direction.

Answer 1

The working fiddle is
https://jsfiddle.net/sesn/y98pz4hj/1/
Here is your answer
button { white-space: normal !important; height: auto !important; }

Answer 2

It will work :
button {
white-space: normal !important;
height: auto !important;
}