Colons for labels conflict with other uses of :

[rbohrer]

This problem will be less serious once #342 is fixed, but my text currently contains a lot of colons in it (because if I make them code mode, the escape characters go wild) and the editor UI misreads my intention as creating a "label" and then displays error about duplicate "labels" in the place where the colon should be (if the same label text appears twice). Some version of this bug will still remain after the other issue is fixed, because I copy-pasted this text into the editor and got the duplicate label errors right away, and could not easily recover the underlying text in the editor, even by converting it to code mode.

(Happy to add reproduction case upon request)

[amyjko]

This is a design flaw in the book markup syntax; it's probably worth reconsidering the use of colon as a label marker.