Select all messages within an actual conversation ...or even select multiple messages in a conversation by date (ex:from 6/1/15 to present...or enter "to" date)...I like saving, and locking certain messages within a thread. I want the option to pick what I want to lock or delete or forward instead of going one by one and selecting bubbles...

Also lets say I want to delete parts of a thread. This would come in handy...i can pick exactly what I want to delete or save... It would be nice if I could lock what I need and just select all to delete and it ask me do I "want to delete locked messages as well"...this way I can lock/delete by date and have the option to delete some or all when needed.