As your content and TuneText is one common script, errors in your code may affect the TuneText functionality.
For example, if you content misses a closing tag for <B>, e.g.,
    <B>...<B>...</B>
this can also make text in the TuneText menus bold.

Click here to download the Web Design Group's HTML 4.0 Reference that was used for developing the TuneText.
Or better, click here to download its Tunetext-enabled copy.

2. Content between <PRE> and </PRE> tags is excluded from TuneText functionality.
This is because these tags are designed for displaying preformatted, -- author's original, - content, which should not be allowed for any re-formatting (editing).

Tip: Use <PRE> if you need to create some Tunetext-disabled areas.

3. You should not mix iframes and normal content.
As iframe creates some restricted area on your screen, this might prevent correct displaying of TuneText menus.

4. If you surround one or several letters with some tag, there will be SPACE between them (to represent each such letter as a word).
For example,

"Ro<B>ma</B>n" becomes "Ro ma n"

This is because tags are separators (switchers) between TEXT and TAG content.

And on the contrary,

"JUMP TO TOPIC" for TuneText is one word:   "JUMP TO TOPIC"

5. You should avoid creating big HTML files.
Generally it's a bad practice to put all available data in one or two files.
In the case of TuneText, the performance partly depends on the number of used words at the page. While such a delay is practically not visible in small files, - it's a matter of milliseconds! - scanning all available words in big files may significantly slow down initial loading, as well as saving edits.
Recomended file size should not exceed 20Kb.