Forcing a stage to only fire manually? Is this possible?

[Sauron]

Okay, so there's a story here I was flying a probe mission to Laythe this afternoon and everything was swell up until the point where I realized that I'd stuffed up my fuel lines and stages (my fuel tanks were separated from the NERVA on a truss). Mission control heroically saved the situation by repeatedly manually balancing the two remaining fuel tanks. Everything went off fairly well with only a minimal amount of insane pinwheeling through space. However, once one of the two side tanks ran out, the decouplers, well, decoupled, taking all my oxidizer with them

So therein lies the question: I really want to set certain decouplers (as well as other things like the fuel vent part or the rocket engines on an ssto, and especially parachutes) that normally automatically(?) appear in the staging so they can only be activated manually with a number key rather than going off automatically or with a space-bar press.

The second question/possible problem is this: this situation (stages firing automatically) mostly seems to happens when my staging looks like this: Activate Engine > Decouple Tanks (Tanks are empty) > Decouple Tanks (tanks are empty) and so on, so it's only a problem when I'm using drop-tanks or asparagus staging (am I correct here--is what I'm describing a thing?)

[entaran]

Turn off mechjeb's auto staging.

Hit Alt-L to lock stages.

Rightclick your decouplers.

[stupid_chris]

Indeed, your problem is probably MechJeb's autostage. The last dev build fixed this problem though, you might want to grab it.

Else, you could set your decouplers to an action button and put them all in a separate stage at the topmost of your staging sequence. This way they will be the last to stage, probably after your lander/probe is decoupled, meaning they won't stage at unexpected moments, and when you want to get rid of them, you just press your action button and there they go

[Sauron]

Huh? I wasn't flying with MechJeb turned on at the time (I only use it for the launch) does the autostage function happen even then?

[Nao]

You can edit staging during flight, just create a new stage put the decouplers in it and move it to top of the stack. That's how i do it If i want something to not fire during normal staging.

You can then deouple them both at the desired time by just moving the created stage to the bottom of the stage stack and pressing space

[stupid_chris]

Huh? I wasn't flying with MechJeb turned on at the time (I only use it for the launch) does the autostage function happen even then?

Yes, that's the bug, the autostage is functioning at all times, even if you don't want it to. You could try creating a new stage and it would automatically go through it because MechJeb is working like this right now. Theres two solutions to this: either you deactivate the autostage after launch, either you download the new dev build, The_Duck fixed the issue, it's working properly now