This is valid since GeneXus version 6 Evolution I:

• If you put the attribute followed by a ‘.’ (full stop), a combo box with the list of properties and possible methods for that attribute appears right after.
• By marking one or several lines (it can be marked with the bar on the left) and then pressing Ctrl-Q the whole block is commented. By pressing Ctrl-Shift-Q it removes the two bars of commentary of the selected block. 
• ‘Bookmarks’ can be used: pressing Ctrl-F2 they are marked, and with F2 you move among them.