twitter bootstrap 3 input-group-addon with btn-group not the same size

Question

I have to make an input-group-btn in twitter bootstrap with a dropdown-menu attached to it but the output image below shows that the btn-group is not of the same size with the input group.

Here is the html code:

<div class="row">
<div class="col-md-2"><button type="button" class="btn btn-primary" onclick="showModalAddStation();">Add Station</button></div>
<div class="col-md-4">
     <div class="form-group">
        <div class="input-group">
        <div class="input-group-btn" >
            <div class="btn-group"> 
                <button class="btn btn-default btn-sm dropdown-toggle" type="button" data-toggle="dropdown">
                    <span data-bind="label" id="searchLabel">Search By</span> <span class="caret"></span>
                </button> 
                <ul class="dropdown-menu" role="menu">
                    <li><a href="#">1</a></li>
                    <li><a href="#">2</a></li>
                    <li><a href="#">3</a></li>
                </ul>
            </div>
        </div>  
        <input type="search" name="searchBy" id="searchBy" class="form-control" />
        <span class="input-group-btn">
            <button id="filter" class="btn  btn-primary btn-block glyphicon glyphicon-plus" onclick="searchStationTable();"></button>
        </span>
        </div>
     </div>
</div>

Answer 1

Your problems are :

1. The button of dropdown-menu you have btn-sm class, it will decrease size of button http://getbootstrap.com/components/#btn-dropdowns-sizing

   solution : remove btn-sm class

2. You are using glyphicon on the button.

   solution : you can use span, i tag or else on button if using glyphicon http://getbootstrap.com/components/#glyphicons-how-to-use

---

<div class="row">
<div class="col-md-2"><button type="button" class="btn btn-primary" onclick="showModalAddStation();">Add Station</button></div>
<div class="col-md-4">
     <div class="form-group">
        <div class="input-group">
        <div class="input-group-btn" >
            <div class="btn-group"> 
                <button class="btn btn-default dropdown-toggle" type="button" data-toggle="dropdown">
                    <span data-bind="label" id="searchLabel">Search By</span> <span class="caret"></span>
                </button> 
                <ul class="dropdown-menu" role="menu">
                    <li><a href="#">1</a></li>
                    <li><a href="#">2</a></li>
                    <li><a href="#">3</a></li>
                </ul>
            </div>
        </div>  
        <input type="search" name="searchBy" id="searchBy" class="form-control" />
        <span class="input-group-btn">
            <button id="filter" class="btn btn-primary btn-block" onclick="searchStationTable();">
                <span class="glyphicon glyphicon-plus"></span>
            </button>
        </span>
        </div>
     </div>
</div>
</div>

http://jsfiddle.net/1hm7thq5/