What used to be RT::Extension::QuoteSelection has been integrated into the RT 5 core. Is there any chance in a future RT version of making this user-configurable? Some of our users really don’t like it (also it’s still broken with respect to long lines in the original text) but the only way of turning it off is to hack the RT source and thus disable it for everyone.
Both of these are in RT 5.0.4. It’s a user preference and we improved the selection logic to limit it to items in the ticket history.