The bug

When starting Minecraft manually with the --demo flag for a non-demo account the icons that appear on the right of the "Minecraft Realms" button are still there, but the button itself is not visible.

Expected would be that the game behaves consistently: When started with --demo is should only respect that flag and ignore whether the account is actually a demo account or not. The icons should not be visible.

Reproduction steps (Windows)

1. Create a script file called start.cmd with the following content:

   "C:\Program Files (x86)\Minecraft Launcher\runtime\java-runtime-alpha\windows-x64\java-runtime-alpha\bin\java.exe" %* --demo
   

   For newer launcher versions or depending on your installation directory you might need to adjust the java.exe path.

2. In the launcher edit the installation for the latest release (for snapshots Realms is not available), click on "More Options" and as "Java Executable" specify the file path of the start.cmd script you created in step 1.
3. Make sure you are logged in with a non-demo account
4. Start the game