Steps to repro:
1. Press play and select canvas
2. Set 'Render Mode' to 'Screen Space - Camera' and switch back to 'World Space'
3. Observe that view didn't change when switched back to 'World Space'
4. Set 'Render Mode' to 'Screen Space - Overlay' and switch back to 'World Space'
5. Notice that 'Render Mode' changed successfully

Expected behavior: Setting 'Screen Space - Camera' -> 'World Space' would influence the game view
Actual behavior: Changing the Render Mode 'Screen Space - Camera' -> 'World Space' doesn't change anything

See video: http://screencast.com/t/YRfrBsLCwETI

Note: happens only when 'Event Camera' is set to the main camera