Copy the following into your wiki page:
<gallery mode="packed-overlay">
File:Image.png|link=Foo|Air Assault
</gallery>
You'll notice this generates the markup:
<ul class="gallery mw-gallery-packed-overlay">
<li class="gallerybox" style="width: 122px">
<div style="width: 122px">
<div class="thumb" style="width: 120px;">
<div style="margin:0px auto;">
<a href="/wiki/Foo">
<img alt=""
src="http://upload.wikimedia.org/wikipedia/commons/thumb/3/34/Image.png/180px-Image.png"
width="120" height="120" data-file-width="500" data-file-height="500" />
</a>
</div>
</div>
<div class="gallerytextwrapper" style="width: 100px">
<div class="gallerytext">
<p>Air Assault</p>
</div>
</div>
</li></ul>
which has an unclosed DIV tag (the div <div style="width: 122px">)
this can cause problems with the Minerva skin, e.g. break rendering of footer (see bug 68228 for details)
Version: unspecified
Severity: normal