Complex_Simplicity is the problem. Don't uninstall LS.

Complex_Simplicity gives you a custom popup option, and when enabled, it edits personal\popup.rc. You will see several lines this file before the main popup itself. Remove tham and you should be fine.

AFAIK, a new version of the theme, with this done in a manner that does not break anything, has not yet been released.

If there are more problems, note that you can re-install LS over the top of itself. Doing so, with Omar's Installer, will not replace themes or modules (but will replace non-theme config files).