The Emblem Picker window is used to display and change a Guild Emblem.
The window will appear when you right click on a Guild Registrar (not Guild Emblem) NPC and type the command "/gc emblem". You must be a Guild Master (Guild Rank 0) to change a guild emblem. The Graphic and Color setting controls are used to change the Emblem Appearance. The Accept button is used to save any changes. The Cancel button is used to ignore any changes and close the window.
There is nothing shown when the window is concealed. The window is invisible with no graphics or controls to minimize the amount of memory used. Nothing will appear on the screen when you attempt to activate the window.