Minecraft Server Data Deleted when adding a server!

My Minecraft wasn't maximized, and I entered a new server info, then I maximized it and the details WEREN'T deleted!
Describe what you thought should happen here

My Minecraft wasn't maximised, and I entered a new server info, then I maximized it and the details WERE deleted!
Describe what happened here

Steps to Reproduce:
1. Make sure your window isn't maximised
2. Go in the multiplayer tab
3. Click add server
4. Add some info
5. Maximise your window
6. Your data is deleted!

Love you Mojang!