Bug 11384

After the DOM is modified the CSS selectors should be re-evaluated. Affected selectors: :first-child, :last-child, :only-child, :first-of-type, :last-of-type, :only-of-type, :empty For example: an element that used to be empty would match the :empty selector. If the update added a new child to that element, it should no longer match the :empty selector. Another example: an element that is the only child of its parent would match the following selectors: :first-child, :last-child, :only-child, :first-of-type, :last-of-type and :only-of-type. If we modify the DOM and append another child of the same type, the original element would only match the :first-child selector.