The following shortcuts can be used on the DocumentItems tab:
 

CTRL-A for Edit->Select All

CTRL-B for Edit->Add Blank Line

CTRL-C for Edit->Copy

CTRL-E for Edit->Insert Paste

CTRL-H for Edit->Insert Heading

CTRL-I for Edit->Insert Blank Line                

CTRL-M for Edit->Insert Comment                          

CTRL-R for Edit->Line Attributes

CTRL-V for Edit->Paste

CTRL-W for File->Close Document

CTRL-X for Edit->Cut

CTRL-Y for Edit->ReDo

CTRL-Z for Edit->Undo