In one of my piano compositions the bracket of the piano system is outside of the music frame, in all other piece the bracket is inside. Where I can change this?
The correct position of the brace is outside the frame, i.e. it is expected that the systemic barline should be aligned with the frame edge unless there is a staff label inside it that would prevent that from being the case. It looks to me as if you have edited the name of your piano instrument to be empty, or perhaps just a space, in the score in which the barline is inset from the left-hand edge of the frame.