Originally Posted by GM4Him
The more I think about it, the more I think it should be NOT a pop-up but the game pausing and pulling up a UI panel with all your available Reactions only. So, if an enemy triggers AOO, the game pauses and the UI only shows Melee attack as an option of what you can do. If you're a rogue who hasn't used Sneak Attack, the Sneak Attack button appears as well, giving you the option to use it.

But maybe you wouldn't want to Sneak Attack because the enemy only has 5 HP. That's why it pops up as an option and it's not automatic.

It would work the same for Battlemaster. AOO triggers. Game pauses. Melee attack and all Battlemaster maneuvers pop up on the UI.

For paladin, same thing except Smite options.

So no message popups. Just game pauses and UI presents your options.

I had a discussion on Discord recently, where we agreed that "Popup" is actually a bad term in this case as it's more a functional meaning than a literal one. Most people associate popups with something that gets in your way in the middle of the screen (think websites, recent GDPR annoyances is a good example) but rather a prompt. Something that becomes available and clearly communicated to the player.

I made a quick photoshop image for visual example of what we were talking about, that when a reaction opportunity occurs, player can immediately choose their reaction, or press spacebar to skip (to be consistent with spacebar skipping in dialogue, cinematics etc). Ideally available reactions would be immediately and dynamically represented in the react option with a much prettier UI design than I could ever do.

Screenshot from feedback doc if you'd like to expand on and comment for further iteration.

[Linked Image from i.imgur.com]