Fix key
This key is used to fix and unfix executors.
To fix an executor, press the Fix key and then a key associated with the executor you want to fix.
A fixed executor will stay visible even when you change the page. If the new page already have an executor assigned to this location, you will not be able to reach the executor on the new page unless you unfixed the executor from the previous page.
To unfix an executor you also press the Fix key and then press a key associated with an already fixed executor.
If you unfix an executor with an active cue it will be unfixed unless the executor actually belongs to a different page. In that case it will become Autofixed. You can not have an active executor that isn't visible.
When you run a cue on a currently visible executor and change the page, then the executor will stay visible (and active) - it's called Autofix. This function can globally be turned off in Setup -> Global Settings.
Advanced Functionality
Pressing the 
key and then pressing the Fix key will lock the console. This means that you can't operate it and any faders being moved will not affect the output. You can unlock it again using the same key combination. If you have an external keyboard then you can also press the "Pause" key.