LAD to STL problem

I make a network in LAD and if I use a little too much rungs (or how do you call this) then the editor changes them into STL when I press the save-button.

Is there a way to fix this so that the networks stay in LAD? Or give at least a warning because now I have to retype the whole peace of code back into a LAD-network. And because the editor places a lot of local variables and jumps, this isn't always easy to understand.
I prefer using LAD because it's easier to read, and we also want to keep one part in one network (4 rungs with each 5-6 contacts). And the strange thing is that I have more complicated networks and that they stay in LAD.

So why does he do this in the first place? It's not that complicated to keep it in LAD.
And how come that he displays everything fine, but when I press save it changes.

Kind regards