Many people receive texts asking them to do something. In Textra, once i see a text, i can't mark it unread, then it's lost in the box. I have to create a reminder or task elsewhere to remember to do the task i was asked to do... that's silly! If i could just mark the message as unread, or tag it with a "to-do" label, or move it to a "requires action" folder, or ideally have the ability to do all of those things, like in gmail, it would really help.

I know you've received many votes already (around 3,000?) for a mark as unread feature. I don't immediately see any downside to that, is there a reason it isn't happening?