HTML Tidy warning re XML decl., cleaned source breaks IE

HTML Tidy gives the following warning when an XML Declaration follows a DTD:

line 3 column 1 - Warning: removing whitespace preceding XML Declaration

However placing the XML Declaration before the XHTML DTD causes Internet
Explorer to render in "Quirks mode".

The W3C Validator does not invalidate an XML Declaration following an XHTML
DTD. I suggest bringing HTML Tidy in line with the W3CV, mainly to avoid
this annoying warning.

-Robin Haswell