Please note that there are some hard coded shortcuts inside the RTF text control DigaRTF.ocx which cannot be used for different shortcuts during the work inside the text editing mode.

Ctrl-B = Characters bold
Ctrl-U = Characters underline
Ctrl-I = Characters italic
Ctrl-L = Paragraph left
Ctrl-T = Paragraph center
Ctrl-R = Paragraph right
Ctrl-A = Select all
Ctrl-C = Copy
Ctrl-Insert = Copy
Ctrl-X = Cut
Ctrl-V = Paste
Ctrl-Z = Undo
Ctrl-Y = Redo
Shift-Insert = Paste
Shift-Delete = Undo

Therefore global shortcuts should differ from these shortcuts.