Like many others, I am very frustrated with the new Kile and Ubuntu Janty has chosen it as default. It is ridiculously slow and the text doesn’t do dynamic word wrap (YES, it doesn’t!). There is a tool to “auto-wrap” but it screws up comments if you use % often as I do. After several months of frustration, I finally uninstalled it and reinstalled the old one. I am not a Linux expert and it is actually much easier than I thought. I probably would have done it couple months ago if I know it is that easy. Simply remove Kile from Synaptic and then download and run the correct version of debian package from this site. this site.
btw, if you forgot to uninstall Kile 2.1 before reinstall 2.0, you may end up having some weird problems. One possible culprit is simply the configuration file is corrupted. A simplest solution is to copy a clean copy from some one else. The configuration file of Kile is ~/.kde/share/config/kilerc
Another note, after reinstalling 2.0, it is better to search kile in synaptic and apply force version Lock Version from Package->Lock Version Force Version… Otherwise, it will switch back to 2.1 after the next update.