Описание тега contextual-action-bar
The contextual action bar (CAB) is a temporary action bar that overlays the app's current action bar while data is selected. It appears after the user long-presses on a selectable data item.
The contextual action bar from the 
android platform was introduced in API level 11(Honeycomb) to provide a new way to show contextual actions for selected content instead of the traditional context menu. Although it was introduced in the SDK starting with Honeycomb the contextual action bar is available to lower API versions thanks to various libraries(like the ActionBarSherlock library). The contextual action bar should be preferred to the old context menu because it offers a richer and better user experience. More information about the contextual action bar can be found in: