My centertank is available in the simulation, without any editing, so it should be there. If you are missing it, here is the entry:

[fuel]
Center1    = 2.0,   0, 0, 6924, 0                 /
LeftMain  = -0.4, -25, 0, 2176, 0                
RightMain = -0.4,  25, 0, 2176, 0              
fuel_type = 2                                  
number_of_tank_selectors = 1                    
electric_pump=0

For easier cold and dark.  Load up the C172 and shut everything down EXCEPT AVIONICS.  Then 757 will be CND.

As for undocking windows - it looks like we'll need CS's help on this one.  I would like to use a 2nd monitor for information sources like FMC.