In general there are a lot of issues with the display and interaction of epub documents, many of which have been iterated in previous bugs. Would this be an issue with the backend generator, could there be any role to borrowing code from a Qt app like Calibre, (or epub.js? even though still in development?) I believe this may mean a few buttons that are epub specific for the interface (font size and search etc.) I'm not a coder ony a consumer so if this is ridiculous please excuse...
Hi Ghavamikia, thanks for your interest in Okular. You are surely correct that there are issues with the epub backend. However, the text you posted here is not a helpful contribution to the bug tracker. A bug tracker is used to keep track of individual specific problems with okular. More general considerations like your text are better sent to a mailing list. I will therefore close this bug now as invalid. Please don't take it the wrong way.