Here's an extremely simple page:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<title></title>
<link href="//netdna.bootstrapcdn.com/bootstrap/3.1.1/css/bootstrap.min.css"
rel="stylesheet">
<script src="//code.jquery.com/jquery-2.1.1.min.js"></script>
<script src="//netdna.bootstrapcdn.com/bootstrap/3.1.1/js/bootstrap.min.js"></script>
</head>
<body>
<input type="text" value="foo"/>
<button type="button" class="btn btn-default"
data-toggle="modal" data-target="#dlg">open</button>
<div id="dlg" class="modal fade">
<div class="modal-dialog">
<div class="modal-content">
<div class="modal-body">
<input type="text"/>
</div>
<div class="modal-footer">
<button type="button" class="btn btn-primary"
data-dismiss="modal">OK</button>
</div>
</div>
</div>
</div>
</body>
</html>
I would expect the dialog to really behave as modal, that is, to disallow tabbing to the first input field while open. Additionally, the input field inside the dialog should be focused on open.
This does not happen. The focus is somewhere else on open (probably the open button), and I can tab across all the controls.