BetterSetFocus keeps your arena macros pointed at the right opponent. It rewrites the /cast @arenaN,... line out of combat[/b] so your bar buttons stay in sync with /focus or a quick pick from a floating prep panel.

What it does

Floating panel during arena prep (2 buttons in 2v2, 3 in 3v3). Click to choose which [arena1- arena3] your macros use — handy when you cannot safely /focus (e.g. stealth).
/focus wins when your focus is a live arena enemy; the manual pick is a fallback until you focus someone.
Up to five macros (BSFArenaFocus, BSFArenaFocus2, …) with spells and optional per-slot prefix/suffix lines around the core #showtooltip + /cast block.
[General or Character macro book, per-character saved settings.
Options: Esc → AddOns → BetterSetFocus — or /bsf config]

Slash commands (/bsf or /bettersetf)

/bsf help — command list
/bsf status — arena detection, which @arena slot macros use, macro names
/bsf setup [slot] SpellName or /bsf make — create/update a macro (slot optional)
/bsf refresh— force macro text refresh (out of combat)
/bsf manual clear — clear manual panel pick; follow [/focus only
/bsf macroname [slot] Name — rename macro in /m
/bsf onlyarena on|off — restrict updates to arena instances (default: on)

[b]Install[/b]

Unzip so World of Warcraft\_retail_\Interface\AddOns\BetterSetFocus\ contains BetterSetFocus.toc and the .lua files.
Enable BetterSetFocus on the character select AddOns list.
/reload in-game after updates.

Notes

You place the macros on your action bars yourself (/m).
Macro edits are blocked in combat; the addon queues changes for when you leave combat.
Retail-focused; Interface version is set in the .toc for the current patch you target on CurseForge.