Every page contains a CSS class containing the page title, e.g. "page-Foobar"
(see bug 5795). However, because the behavior is implemented in (at least) two
places, the generated class names differ between skins. In Monobook, the
behavior is correct, but in Standard, the class is escaped wrongly, using
escapeId instead of escapeClass, so that the class name can contain dots (which
is, while syntactically valid, unusable in CSS selectors).
See r17120, esp. the non-change in Skin.php, where escapeId should have been
changed to escapeClass.