TorButton causes significant CPU load
When using TorBrowser without Tor (extensions.torbutton.use_nontor_proxy = true) TorButton tries to connect to control port, fails and then begins to waste CPU cycles by retrying control port connection attempts.
This is due to circuit display code here: https://gitweb.torproject.org/torbutton.git/tree/chrome/content/tor-circuit-display.js#n412
Disabling extensions.torbutton.display_circuit solves this, but it is kinda non obvious from user POV. Please make extensions.torbutton.use_nontor_proxy the only pref needed for TorButton to cease all of its Tor-related activities.