EiffelStudio editor offers the possibility to comment or uncomment several lines at a time.
The "Comment" command corresponds to the Comment entry in the Advanced sub-menu of the Edit Menu. It may be called by using the keyboard shortcut "Ctrl+K". Its action is to insert two dashes in front of each selected line.
The "Uncomment" command corresponds to the Uncomment entry in the Advanced submenu of the Edit Menu. It may be called by using the keyboard shortcut "Ctrl+Shift+K". Its action is to remove the two dashes in front of each selected line if there are such characters.
Note: If there is no selection, these commands will be applied to the current line.