How can I get X1 to search CSS comments?

Damn it!

After *much* testing, it now appears that there is some minor form of corruption in my CSS file which, when the file is saved with a .TXT filename extension X1 Search can still index all the text in that file.
HOWEVER if I save the file with a .CSS filename, suddenly X1 Search can no longer index ANY of the contents of that that file.

Let me try and paste the offending text...
OK so if I save a file called test01.CSS with the following 3 lines of content, then the X1 will NOT be able to find there word TextingX1

TestingX1
xx
final line

Whereas if I save the file still called test01.CSS with this contents... then X1 *will* be able to find the word TextingX1

TestingX1
xx
final line

And bizarrely enough, if I name the file test01.txt, then X1 suddenly can find both versions.
It seems that the rough character is appearing on the second line of text - i.e. the line containing "xx"

J


P.S. Interestingly, if you copy and paste from what I have pasted above, you should be able to duplicate the problem in a new file even though the two pastings look identical.

---