The selection provider of a Spoofax editor now provides StrategoTermSelections (subclass of TextSelection) instead of TextSelections. Besides textselections, a StrategoTermSelection also gives you an AST and an analyzed AST selection. Furthermore, StrategoTermSelections are also generated when the cursor moves around while the textselection stays empty (text selection doesn't change). This all to create support for a properties view.
for now, disable the properties view
bugfix: selectionAST may be null