TrvActionFontStrikeout is the action for "Strikeout" command.
TrvActionFontStrikeout = class(TrvActionFontStyle)
This action does not introduce any new properties in addition to properties of TrvAction.
This action strikes through the selected text (toggle). It adds/removes fsStrikeOut in Style property for styles of all selected text items.
This is a checkbox-like action, its Checked property is updated depending on the state of selection (or the current text style).