When having a cannon selected for aiming (with the clock), left clicking is meant to fire.
As it stands, shift left clicking with ANYTHING fires the cannon, though this shouldnt be the case.
This is because shift left clicking with a compass makes you turn, thus your ship turns and you fire at the same time.
It should probably be set to only fire when holding the clock :)
When having a cannon selected for aiming (with the clock), left clicking is meant to fire. As it stands, shift left clicking with ANYTHING fires the cannon, though this shouldnt be the case. This is because shift left clicking with a compass makes you turn, thus your ship turns and you fire at the same time.
It should probably be set to only fire when holding the clock :)