 
Casual Ediff (casual-ediff-tmenu) is invoked from the Ediff control window, typically using the binding C-o (or your binding of preference).
The menu comprises of sections laid out horizontally that correspond to source of the diffs. The number of sections and their contents are context-dependent on the type of content to be compared.
The following sections are offered in the menu:
Context-dependent commands for Ediff buffer A.
Context-dependent commands for Ediff buffer B.
Context-dependent commands for Ediff buffer C, if available.
Ediff commands not related to a specific buffer.
Navigation between diffs are bound to the p and n keys for previous and next diff respectively.