Long instrument names appear at wrong system

Load the attached file. Edit anything in the second system (insert note, drag a dynamic, ...). The system shows now long instrument names. You may repair that by performing a save. But this is nerve-racking when editing bigger scores, because layout is changing permanent.

The reason seems to be, that after each editing activity the layout is refreshed only for a range of the score, but the call

system->setInstrumentNames(lc.startWithLongNames);  (layout.cpp ln. 2904) 

takes "startWithLongNames" for the top of the refreshed range instead of the top of the score. A simple hack at the above line avoids the effect, but the cause of the problem should be solved.