I've just had to rollback DE 4.0 to DE 3.0 because DE 4.0 screwed up the formatting for my Trigonometry For Dummies 2nd Ed ebook: Mouse wheel won't scroll through all the book, only small sections of it. Ditto the search can only search small sections not the entire book. The font is really small and looks like Times Roman. Graphics images not displaying properly. After rollback to 3.0 everything's working okay again. Developers: You should test your upgrades more rigorously!
Thanks for your advice shreya. I didn't give the full DE version number in my post but it is in fact the latest version 4.0.1 that I was referring to. I've tried it again just now and still doesn't work properly with my Trigonometry For Dummies ebook; 3.0 does so I'll have to uninstall 4.0.1 again and reinstall 3.0.