e.returnValue = false;
to stop the link for the item tag from performing its default operation (doing a GET for the href value). This no longer seems to work in IE11. I have substituted
e.preventDefault ? e.preventDefault() : e.returnValue = false;
which seems to work. I can now make choice selections in the TOC.
Doing a search for ".returnValue" over all source code reveals several matches. I am substituting the same line for all occurrences, I hope nothing bad happens.
I would submit a patch but
a) It is beyond my skill level
b) I don't know if I have done a good thing or a bad thing
Bottom line - it worked for me but I'm not responsible if it causes your keyboard to catch fire.