Add line breaks at end of each system ignores horizontal frames
S4 - Minor
If a system contains a horizontal frame somewhere in the middle or at the end, and you use Tools / Add/Remove Line Breaks then choose the option to add line breaks at end of each system, the break is added to the measure before the frame. Seems like we are taking "system" too literally here, should really be "system row" internally.
Conveniently for the case at hand for me, this doesn't happen if the last measure before the frame is a mmrest.