Full Measure Copy and Paste may crash IF there is another section in different key / time signature
Create a Basic Score in 4/4 any Key. Copy and Paste any repeated full-measure figure to a different measure at will. Now add another section to the piece ( i.e. Sonata Second Movement in 3/4, Dominant Key ). Try a Copy / Paste of any repeated full-measure figure (still within that movement), or within the previous first movement. MuseScore CRASHES every time. REMOVE the second movement: Everything works fine. Will send 10 second send screen movie if desired. Anxious awaiting Version IV in order to utilize symphonic instrument voice plug-ins. MuseScore developers are fabulous. Herculean task. Awesome results. A tip of the plumed hat to all of you. Stay safe, and blessings for the New Year.