Replying from pulling down notification bar doesnt work

The app works pretty well, it is good to use to talk with friends in other countries. My messages go through most times. However the a pull down option does not work. It pops up at the top and I can pull down and start typing my reply without opening the app but as soon as I press send it opens the app, erasing my reply in the process,
This is incredibly annoying, especially when the reply I was sending was lengthy and most of the time I cannot remember what I typed. Please fix this.

ERtfjdjdjjxjdjr about WhatsApp Messenger