Quick Question : WP 8.1 Messaging app

I have a qn about how msgs work on the dual sim. hope I m right that we have two msg inboxes one for each sim.

what if I get a msg on SIM 1 and I need to reply via SIM 2, so should keep moving from one msg app to another to carry on the conversation? that doesn't sound smooth to me.

FYI, on Android, you have a single msg inbox and while you press send, you can choose from which SIM you can send the msg.