Don't do preservative rendering in text-property.
Don't do preservative rendering in text-property.

This didn't have any notable effect on flickering.

podviaznikov/substance,michael/substance-1,GerHobbelt/substance,jacwright/substance,substance/substance,substance/substance,TypesetIO/substance,andene/substance,TypesetIO/substance,abhaga/substance,abhaga/substance,DuncanAForbes/substance,DuncanAForbes/substance,podviaznikov/substance,stencila/substance,andene/substance,michael/substance-1,jacwright/substance,GerHobbelt/substance