Flashforge Creator Pro - Extruder is loose?

[EagleSeven]

I remove my nozzles, and was about to replace my PTFE tubing inside. but I notice the heater-block is loose from the cylinder which I guess it's attached to somehow.

I can't figure out how its held in place?

Added picture for better explanation.20151010_124157.jpg

The Nozzle is what tightens up that assembly.
The nozzle screws in until it hits the tube (cylinder),
preventing Both from turning in the block.

The Block should be slightly loose on tube until the nozzle is installed.

So, how far the tube is screwed into block controls how far the nozzle will screw into block,
before they touch.
Both seated together (touching) prevents any filament getting into threads of tube and nozzle.