+1; good suggestion.
I'll hijack this thread to also advocate for a single-action "undo" button (ideally for actions that don't involve rolls).
- You move slightly too far and can no longer target a creature with some spell? Undo that move, as long as you didn't provoke any AoOs along the way.
- You accidentally click an icon that uses up a resource you don't want to use? Undo.
- You cast a spell that cancels your previous concentration spell? Undo.
Basically, this would cover all situations where in tabletop you'd say to the GM: "Oh, I didn't realize that would work that way. Can I do this instead?" along with fixing the accidental button presses that can ~only happen in video games.
- E.g., in Solasta I'll often click the "swap equipped weapons" button, and then realize I actually want to use an inventory item, but can't because I've used my free item-interaction for the turn. However, as I haven't actually used my swapped weapon yet, imo it's reasonable for me to undo the swap.
This would obviously be more work than a dedicated Concentration-related-warning, but it's in a similar category of player-friendly mistake-fixing tools.