I have been working on several booklets for a client and after desiging the print version, we've been creating epub versions to be offered from their website. I've had the same issue arise twice now, with two different files.
The ID documents are created with Word docs that have some left over paragraph styling, which doesn't show in the print version, but require finding and fixing during epub exports. I have started out exporting the files to epub just fine, using the Paragraph Style that I had chosen for the Chapter Titles as the page break choice in the Advanced export tab in the Split Document dropdown list. It's worked multiple times, then suddenly reverts to Do Not Split, and the Paragraph Style for the Chapter Titles has dissappeard from the drop down list. The first time this occurred, I tried duplicating, renaming and changing the Paragraph Style used, but that new style didn't appear in the dropdown list either. For that file, I finally gave up, reverted to working with an older epub I luckily had, and hand fixed all the issues in the HTML files. Not fun.
However, it's a month later, and this same glitch has occurred in another file. Has anyone experienced this problem, and is there a fix for it? Would really appreciate some help with this one.