Micro Menu

The Micro Menu is a collection of small buttons located between the main Action Bar and the character's bag slots. The buttons open various UI panels.

Icon	Functionality
Current Elements
	Character Info window (sometimes called the "paper doll"). The icon changes to match the character's appearance.
	Spellbook & Abilities window which includes companions and mounts.
	Talents window which includes glyphs.
	Achievements window (includes Statistics). Introduced in Patch 3.0.
	Quest Log; Icon changed from .
	Guild window. The icon changes to match the character's guild crest. As of Patch 4.1, changes to Guild Finder button if character not in a guild. Replaced Socials window in Patch 4.0.1.
	Player vs. Player window (honor and arena points, as well as battleground queueing). The icon changes to match the character's faction. Introduced in Patch 3.0.
	Dungeon Finder window. Replaced LFG/LFM window in Patch 3.3.0, which also replaced the World Map button in Patch 2.0.
	Options (Game Menu) window (Help, Options, Interface, Key Binding, Macros, Logout, Exit Game, and Return to Game). Since Patch 3.0, the monitor changes color based on your latency (green, yellow, or red). As of Patch 4.0.1, icon changes to when streaming non-critical data downloaded in the background. Icon replaced from .
	Help Request for making Game Master tickets and other options via the Customer Support window.
Added in Patch 4.2
	Dungeon Journal window.
	Socials window, but defaulting to Raid List and showing "Raid" as a tooltip.
Old Elements
	Socials window (Friends List, Ignore List, Who List, Guild List, Raid List) Replaced by the Guild button in Patch 4.0.1.
	World Map window.
	Latency status bar; changes color based on connection latency. Merged with the Options button in Patch 3.0.0.

In Patch 4.2 Edit

The button is the new Dungeon Journal introduced in Patch 4.2. The button is for the Socials window, but defaults to the Raid tab by design (not sure who really wanted it though).