Qt Creator freezes while typing, copying, cutting, etc. on Ubuntu 14.04

I've installed Qt Creator from https://www.qt.io/download-open-source/ on two Ubuntu 14.04 machines and both editors freeze every once and a while when I'm editing. I have a project that's using CMake, with only several small files. It usually freezes for about 10 seconds or so, almost randomly but more so when doing Ctrl+C or Ctrl+X (for copying and cutting).