Включить/выключить перенос по словам.
Расположите на форме 2 элемента CommandButton.

Const WM_USER = &H400
Const EM_SETTARGETDEVICE = (WM_USER + 72)
Private Declare Function SendMessageLong Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long

Private Sub Command1_Click()
SendMessageLong RichTextBox1.hwnd, EM_SETTARGETDEVICE, 0, 1
End Sub
Private Sub Command2_Click()
SendMessageLong RichTextBox1.hwnd, EM_SETTARGETDEVICE, 0, 0
End Sub