Make select option XHTML compliant for "Number of lines to display".

http://validator.w3.org/check
"SELECTED" is not a member of a group specified for any attribute
<option value="7" SELECTED >7</option>

The name and VI delimiter can be omitted from an attribute specification only if SHORTTAG YES is specified
<option value="7" selected >7</option>

"VI delimiter" is a technical term for the equal sign. This error message means that the name of an attribute and the equal sign cannot be omitted when specifying an attribute. A common cause for this error message is the use of "Attribute Minimization" in document types where it is not allowed, in XHTML for instance.

How to fix: For attributes such as compact, checked or selected, do not write e.g <option selected ... but rather <option selected="selected" ...