I've actually thought about this problem before so thanks for bringing it up so that I could think about it again. Here is some code that will move the cursor position to the spot where you right click
VB Code:
  1. Option Explicit
  2. Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long
  3. Private Const WM_USER = &H400
  4. Private Const EM_CHARFROMPOS = WM_USER + 39
  5. Private Type POINTL
  6.         x As Long
  7.         y As Long
  8. End Type
  9.  
  10. Private Sub RTB_MouseDown(Button As Integer, Shift As Integer, x As Single, y As Single)
  11.     Dim mypoint As POINTL
  12.     Dim Index As Long
  13.     If Button = vbRightButton Then
  14.         mypoint.x = ScaleX(x, vbTwips, vbPixels)
  15.         mypoint.y = ScaleY(y, vbTwips, vbPixels)
  16.         Index = SendMessage(RTB.hwnd, EM_CHARFROMPOS, 0, mypoint)
  17.         RTB.SelStart = Index
  18.     End If
  19. End Sub
Now it is just like the left mouse button