JQuery Mobile combobox not 100% after selecting

I am using the latest version of JQuery Mobile

I have a combobox which takes up the 100% width.

Up to there it's fine.

My problem is that as soon as I open it and make a selection it expands t开发者_运维百科o about 140%.

Has anyone had this problem before? Any ideas how to fix it?

My viewport is:

<meta name="viewport" content="width=device-width, initial-scale=1">

and here's the select:

<label for="opt1" class="select">Options</label>
<select name="opt1" id="opt11">
    <option value="0">No Option</option>
    <option value="1">Option 1</option>
    <option value="2">Option 2</option>
</select>