Bootstrap scrollspy doesn't work inside tabs?

Question

Below is my code, but I know there is nothing wrong with it, because it works fine when you take it out of the tab. There are also no duplicate Id's, which I thought might be causing the problem. Anyway, if anyone has any ideas or workarounds that would be great!

<div id="sampleNavbar" class="navbar navbar-static">
    <div class="navbar-inner">
        <div class="container" style="width: auto;">
            <a class="brand" href="#">Project Name</a>
            <ul class="nav">
                <li><a href="#PA">PA</a></li>
                <li><a href="#VT">VT</a></li>
                <li class="dropdown">
                    <a href="#" class="dropdown-toggle" data-toggle="dropdown">Dropdown <b class="caret"></b></a>
                    <ul class="dropdown-menu">
                        <li><a href="#uno">uno</a></li>
                        <li><a href="#dos">dos</a></li>
                        <li class="divider"></li>
                        <li><a href="#tres">tres</a></li>
                    </ul>
                </li>
            </ul>
        </div>
    </div>
</div>
<div id="scrollspy-example" data-spy="scroll" data-target="#sampleNavbar" data-offset="300" style="height: 200px; overflow-y: scroll;">
    <h4 id="PA">PA</h4>
    <p>Ad leggings keytar, brunch id art party dolor labore. Pitchfork yr enim lo-fi before they sold out qui. Tumblr farm-to-table bicycle rights whatever. Anim keffiyeh carles cardigan. Velit seitan mcsweeney's photo booth 3 wolf moon irure. Cosby sweater lomo jean shorts, williamsburg hoodie minim qui you probably haven't heard of them et cardigan trust fund culpa biodiesel wes anderson aesthetic. Nihil tattooed accusamus, cred irony biodiesel keffiyeh artisan ullamco consequat.
    </p>
    <h4 id="VT">VT</h4>
    <p>Veniam marfa mustache skateboard, adipisicing fugiat velit pitchfork beard. Freegan beard aliqua cupidatat mcsweeney's vero. Cupidatat four loko nisi, ea helvetica nulla carles. Tattooed cosby sweater food truck, mcsweeney's quis non freegan vinyl. Lo-fi wes anderson +1 sartorial. Carles non aesthetic exercitation quis gentrify. Brooklyn adipisicing craft beer vice keytar deserunt.
    </p>
    <h4 id="uno">uno</h4>
    <p>Occaecat commodo aliqua delectus. Fap craft beer deserunt skateboard ea. Lomo bicycle rights adipisicing banh mi, velit ea sunt next level locavore single-origin coffee in magna veniam. High life id vinyl, echo park consequat quis aliquip banh mi pitchfork. Vero VHS est adipisicing. Consectetur nisi DIY minim messenger bag. Cred ex in, sustainable delectus consectetur fanny pack iphone.
    </p>
    <h4 id="dos">dos</h4>
    <p>In incididunt echo park, officia deserunt mcsweeney's proident master cleanse thundercats sapiente veniam. Excepteur VHS elit, proident shoreditch +1 biodiesel laborum craft beer. Single-origin coffee wayfarers irure four loko, cupidatat terry richardson master cleanse. Assumenda you probably haven't heard of them art party fanny pack, tattooed nulla cardigan tempor ad. Proident wolf nesciunt sartorial keffiyeh eu banh mi sustainable. Elit wolf voluptate, lo-fi ea portland before they sold out four loko. Locavore enim nostrud mlkshk brooklyn nesciunt.
    </p>
    <h4 id="tres">tres</h4>
    <p>Ad leggings keytar, brunch id art party dolor labore. Pitchfork yr enim lo-fi before they sold out qui. Tumblr farm-to-table bicycle rights whatever. Anim keffiyeh carles cardigan. Velit seitan mcsweeney's photo booth 3 wolf moon irure. Cosby sweater lomo jean shorts, williamsburg hoodie minim qui you probably haven't heard of them et cardigan trust fund culpa biodiesel wes anderson aesthetic. Nihil tattooed accusamus, cred irony biodiesel keffiyeh artisan ullamco consequat.
    </p>
    <p>Keytar twee blog, culpa messenger bag marfa whatever delectus food truck. Sapiente synth id assumenda. Locavore sed helvetica cliche irony, thundercats you probably haven't heard of them consequat hoodie gluten-free lo-fi fap aliquip. Labore elit placeat before they sold out, terry richardson proident brunch nesciunt quis cosby sweater pariatur keffiyeh ut helvetica artisan. Cardigan craft beer seitan readymade velit. VHS chambray laboris tempor veniam. Anim mollit minim commodo ullamco thundercats.
    </p>
</div>        

Answer 1

This isn't a bug in Bootstrap. What's happening is that, when your page loads, the tab with the scrollspy elements is hidden. As such, when the scrollspy plugin attempts to find the $.position() of each <h4 id="foo"> within your scrolling div, they call return {top: 0, left: 0}. That's why you see the flickering as you scroll; the plugin thinks all your scroll targets are in the same position.

If you look at the documentation for the scrollspy plugin, you'll see that it mentions that if you are adding or removing elements from the DOM, you need to call the .scrollspy('refresh') function so that the plugin can reassess the positions of the various scroll targets.

That said, what you need to do is wait until the tab with the scrollspy content is loaded, and then call the refresh function, like so. Note that I've also combined all the separate click handlers into one handler

$(function(){
    $('.nav-tabs li a').click(function(e) {
        e.preventDefault();
        $(this).tab('show');

        // If we are showing the scrollspy tab, let the
        // plugin refresh itself so it can function properly
        if(this.id === 'scrotab') {
            $(this).on('shown',function(){ 
                $('#scrollspy-example').scrollspy('refresh'); 
            });
        }
    });
});

Also, rather than using a data-offset="300" attribute on your <div id="scrollspy-example"> element, you need to set the position of the element to relative with CSS:

#scrollspy-example {
    position: relative;
}

Here's a jsFiddle Demo that works:

http://jsfiddle.net/GyMYE/3/

Answer 2

Adding:

$('#scrollspy-example').scrollspy('process');

after the:

$('#scrollspy-example').scrollspy('refresh');

makes sure that the correct position is updated as you load this particular tab. Otherwise the wrong li element will be highlighted by scrollspy until you move/start scrolling, causing the refresh. The 'process' line performs this on tab load.