Group/ungroup button enhanced, and/or grid left-aligned
parenthesizing expressions
LimitPositioning deactivated: underscript stays always underscript
Replace proof choice improved if tabs have been skipped
KB rewriting, expanding defs, elementary substitutions

KB rewriting looped due to wrong recording of applied rules
Elementary substitution improved: formula stays in KB
After expanding a definition, the unexpanded formula goes into an
auxiliary KB (optional component in PRFSIT)
Proof display: entire proof sit is displayed for open sit
Expansion of definitions (proving conditions)

plus bug fix in proof text noApplicableRule