The Gallery control implements Microsoft Ofiice 2007-style gallery. A gallery is organized as a set of groups, where each group may have its own caption and each group item may have an image and text.

Currently the Gallery control works in three modes: Compact, Full and Menu.

In the Compact mode the Gallery is represented as a set of images layed out as a palette. There are two scroll buttons and one button, which opens the Gallery in the Full mode,  at the right side of the palette. Group captions are not displayed in this mode.

In the Full mode the Gallery looks like a popup menu, where a group caption takes the full width of the control and next to the caption goes a palette with group items. Each item is represented by its image (texts are not used in thos mode). A Gallery may contain several groups.

The Menu mode is a special type of the Full mode. You must set the IsMenuMode property to true in order to enable menu mode. In the Menu mode the gallery still displays group captions, but all items are layed out like the regular popup menu items. You can set up the menu to draw manu margin, show checked and pressed states, specify item margins (which affect the height of gallery items) and so on. 

You need to initialize the GalleryGroupItems collection with GalleryGroup objects to make the Gallery to display groups.

When the Gallery control has been initialized, it buids an internal flat list of items of the GalleryCommandObject type. Group captions are also treated as items, so if you need to find out an index of a specific item, you need to take into account the caption items.