On firefox 35.0.1, using navbar-top-fixed from bootstrap as a top menu, having a map underneath in a row div. When clicking the tabs, my window position is moved down. Leaflet.
<header class="header clearfix navbar navbar-fixed-top" style="padding:0; background-color: #484848; margin-bottom: 0px; border-radius: 0px;z-index: 3000;" >
<div class="container" style='margin-left: 0px;'>
<div class="row">
</div>
</div>
</header>
<div class="row">
<div class="col-md-12" style="padding:0px; margin-top: 65px;">
<div id="map" style="height:600px" ></div>
<!-- **************************************** MAP TABS ***************************************** -->
<div id="sidebar" class="sidebar collapsed" style="top:85px;">
<!-- Nav tabs -->
<ul class="sidebar-tabs" role="tablist">
<li><a href="#home" role="tab"><i class="fa fa-bars"></i></a></li>
<li><a href="#profile" role="tab"><i class="fa fa-user"></i></a></li>
<li><a href="#messages" role="tab"><i class="fa fa-envelope"></i></a></li>
<li><a href="#settings" role="tab"><i class="fa fa-gear"></i></a></li>
</ul>
<!-- Tab panes -->
<div class="sidebar-content active">
<div class="sidebar-pane" id="home">
<h1>sidebar-v2</h1>
<p>A responsive sidebar for mapping libraries like <a href="http://leafletjs.com/">Leaflet</a> or <a href="http://openlayers.org/">OpenLayers</a>.</p>
<p class="lorem">Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.</p>
<p class="lorem">Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.</p>
<p class="lorem">Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.</p>
<p class="lorem">Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.</p>
</div>
<div class="sidebar-pane" id="profile"><h1>Profile</h1></div>
<div class="sidebar-pane" id="messages"><h1>Messages</h1></div>
<div class="sidebar-pane" id="settings"><h1>Settings</h1></div>
</div>
</div>
</div>
</div>
'''