Qt Creator is continuously indexing slowing down the editor and making auto-complete very slow.

Downloaded the official 2.8 version to use on a software development comprising a session with multiple projects open at the same time.
I found that the indexing progress bar continuously pops up every 10s or so or more frequently while I'm typing code. This results in a) continuous visual distraction but more importantly b) the editors slow right down causing the auto-complete feature to become unusable. I have since uninstalled 2.8 and reverted to previous 2.7.0 (with Qt 5.0.2) until this is resolved.