The Bug:
You can no longer join a Realm quickly by double-clicking on it from the Realms panel.

Steps to Reproduce:

1. Own or be able to join a Realm you are invited to.
2. Open the Realms panel by clicking the "Minecraft Realms" button from the title screen.
3. Click on a listed Realm twice in quick succession.
4. Note that this only highlights the Realm, but you must click the "Play" button on the bottom in order to join it.

Observed Behavior:
Clicking twice quickly on a listed Realm that you are normally able to join does not let you join the Realm.

Expected Behavior:
Clicking twice on a listed Realm that you have access to in quick succession would allow you to instantly join the Realm without having to click the "Play" button on the bottom of the screen.

(The changelog for 1.19.4 mentioned that the Realms menu was changed "to be more in line with the Singleplayer and Multiplayer screens," but I wanted to confirm that this was intended behavior, as this was a nice feature for convenience that I personally used often.)