Server settings dont display straight away

Steps to Reproduce:
1. Join a partnered server using custom settings (EG: CubeCraft)
2. Open settings
3. Custom settings don't appear without reopening the settings window several times

OR

Steps to Reproduce:
1. Setup a custom server using https://github.com/CloudburstMC/Protocol
2. Open the settings menu on the client
3. After the client sends a ServerSettingsRequestPacket, respond with a form in a ServerSettingsResponsePacket
4. Custom settings don't appear without reopening the settings window several times

Observed Results:
Custom settings don't appear without reopening the settings window several times

Expected Results:
Custom settings appear as soon as the menu gets opened the first time if the client receives some
 

Likely another issue but it also hides the menu when the game window is unfocused until you click back onto the window (windows 10 edition).