Staging focuses on used stage

[KerbalisticMissile]

My IKKM (Inter Kontinental Kerbalistic Missile)'s final liquid fuel rocket stage always draws the focus away from the warhead when separated, so I can not do the final stage. I even aimed the camera at the RMG and pressed control from here, but it still focuses on the spent stage. Also, whenever I remove one part with staging, EVERY other part with staging gets messed up. I have procedural parts mod, tweak scale mod, and KSP 1.2.2. This is my first working multi-stage (8 stages, 80+ parts, 9 engines) rocket, so I don't know too much about staging. Where can I upload the file?

Edited September 29, 2017 by KerbalisticMissile

[Snark]

Hello, and welcome to the forum! 

Moving your technical-support question about your modded game to the technical support forum for modded games.  (Science & Spaceflight is for discussion about real-life stuff, not KSP.)

[Bluastrid]

Change your root part in the VAB for the uppermost stage's control part.

[Zhetaan]

@KerbalisticMissile:

@Bluastrid has it right.  These sorts of issues are almost universally a root part problem.  The re-rooting tool available in the editor makes fixing this very straightforward; if you've never used it, it's the rightmost in the bank of four tools (going from left to right:  place, offset, rotate, root).  Click it, click your rocket, and click the part that you want to be the root part.  That part ought to be the probe core or whatever the control unit is for the warhead.  You will probably need to redo your staging one more time after re-rooting, but hopefully that will fix it.

I'm not entirely certain what you mean when you say that removing a part with staging messes up the other parts except perhaps that you mean to say it messes up the order of stages, but that is usually caused by root-part problems, as well.