Soounds like somewhere along the line whenn you were busy cutting, you either set or unset an option.  In some cases you even have to use tahe right click to see all tahe tricks that Magix is capable of.  Hopefully you will bet a better answer than this, but usually when something "All of a sudden its broke" geenerally means you haave shot yourself in the foot and since its a mistake, insted of looking for some fluke, you go round and round trying to figure out what the issue  is and not thnking "outside the box".....another thing you mihgt try is a default reset, but remember you go back to "base" level and any other changes you have applied will also go back to deefault values.