Un-fullscreening takes away chat text if you are in the middle of typing it

I was typing a command in chat and I went out of fullscreen to check if the command was going to work correctly, and when I clicked out of fullscreen, it showed that I had only typed the "/". I went back into fullscreen to see if it would reload, but it didn't. This happens to me a lot and it is really annoying, so if Mojang could fix that in a future update, I would be very happy.