Just to muddy the water a bit, some radios did not have their "neutral center" actually at center. This gave the effect that, on switching the servo reverse, the servo would take up a new position, or the ESC would gain a new neutral position. Getting technical, while the rest of the world liked 1.5mS pules as neutral, with longer being forward and shorter being reverse, Futaba liked 1.25mS for center, and the opposite direction logic. Still within the limits of the "standard", but different enough to try to achieve a "lock-in".
The old style sets had switches to set between "N" &"R" and a mechanical slider to trim the center point. Computer sets do it via their programming, some low cost sets use press buttons for trim because they are cheaper to arrange than the mechanical equivalent. The downside of this is that there is no visual indication of where you are up to.