MS Word VBA Macro from validation - vba

Question

I'm trying to do what, I think, ought to be the simplest of things, but I can't get it to work. i have an MS Word document with a number of legacy drop-down and text fields:
The first option in each drop-down is "Select ...", and if a user tabs out of one of the drop-downs without choosing something other than the first "Select ...", I want a msgbox to appear to tell them to make a selection, which works. What doesn't work, is that after the user dismisses the msgbox, I want the insertion point to return to the drop-down that they didn't select.
I understand that VBA has "timing issues", and from what I've read, one way to address these timing issues is to call the "return" macro from the validation macro. So I've written two macros:
Sub Validate()
' Dim strBookmark As String
' strBookmark = Selection.Bookmarks(1).Name
10: If (bool_debug) Then MsgBox ("NotSelected() - 10: strBookmark = " & strBookmark)
With ActiveDocument
If (strBookmark = "Locality") Then
Call Salary_Step
ElseIf (strBookmark = "Series") Then
20: If (bool_debug) Then MsgBox ("NotSelected() - 20: .FormFields(strBookmark).Name = " _
& .FormFields(strBookmark).Name)
If ((Len(.FormFields(strBookmark).Result) <> 4) Or (Not IsNumeric(.FormFields(strBookmark).Result))) Then _
MsgBox ("Please enter a 4 digit number.")
Call GoBackToPrevious(.FormFields(strBookmark).Name)
ElseIf (.FormFields(strBookmark).DropDown.Value = 1) Then
MsgBox ("Please select a " & Replace(Selection.FormFields(strBookmark).Name, "_", " ") & ".")
Call GoBackToPrevious(.FormFields(strBookmark).Name)
End If
End With
End Sub
and
Sub GoBackToPrevious(strPreviousField)
10: If (bool_debug) Then MsgBox ("GoBacktoPrevious - 10: strPreviousField = " & strPreviousField)
ActiveDocument.Bookmarks(strPreviousField).Range.Fields(1).Result.Select
End Sub
But when I tab out of any of the form fields, the insertion point jumps to the next form field and not back to the one that I just tabbed out of.
I know from the debug code that GoBackToPrevious is being passed the name of the current form field, but MS Word advances to the next field regardless.
I'd really appreciate it if someone can tell me how make MS Word return to and select the drop-down the user did not select appropriately instead of jumping to and selecting the next form field in the document.
Thank you.
P James Norris
EDIT:
Based on #TimothyRylatt comments, I have modified my macro and when they're called.
I have edited Validate as above (commenting out the Dim the strBookmark assignment, and I call it "on entry" to the next form field.
strBookmark is Dimed on the module's declaration section:
Option Explicit
Const bool_debug As Boolean = True
Const str_password As String = "###" ' I have a different password
Public strBookmark As String
and "on exit" from the "current" form field, I attempt to store the "current" bookmark name:
Sub StoreBookmark()
strBookmark = Selection.Bookmarks(1).Name
10: If (bool_debug) Then MsgBox ("StoreBookmark() - 10: strBookmark = " & strBookmark)
End Sub
which I call from the current form field "on exit".
But when I tab out of the current form field to the next form field, the insertion point doesn't go back to the "current" but instead stays in the next form field.
Anyone have any other suggestions/insights?
Thanks,
P James Norris