Question

Private Sub Workbook_BeforeSave...  
MsgBox "Why"

If Form1 is focused – the MsgBox doesn’t appear. Saving procedure is canceled.
Plese don’t tell me that the end user must click outside the form to save the file.
Form1 is not modal.

Answer 1

please place a textbox on a form, place the cursor inside it, or just
click on form header. Then press Ctrl+S, and see if the MsgBox appears
or not. – Alegro 49 mins ago

In such a case simply paste this code in your userform. This code is slightly modified from my other answer.

CODE (Tried And Tested):

Private Declare Function GetKeyboardState _
Lib "user32" (pbKeyState As Byte) As Long

Private Myarray(255) As Byte

Dim Cntrl_Key As Boolean, Sletter_Key As Boolean

Private Sub TextBox1_KeyDown(ByVal KeyCode As MSForms.ReturnInteger, _
ByVal Shift As Integer)
    If KeyCode = 17 Then Cntrl_Key = True
    If KeyCode = 83 Then Sletter_Key = True
    Call ShowKey
End Sub

Private Sub RefreshKeyState(RefreshState As Boolean)
   If RefreshState Then
      Call GetKeyboardState(Myarray(0))
   End If
End Sub

Private Sub ShowKey()
    '~~> Check for Ctrl + S
    If Cntrl_Key = True And Sletter_Key = True Then
        '~~> Save Workbook
        ActiveWorkbook.Save
        Cntrl_Key = False
        Sletter_Key = False
    End If
End Sub

SCREENSHOT:

NOTE: This is not a foolproof method as a user may press CTRL and then types something else and then presses the “S” key then the code will still fire. We can include a small check to see if the next key pressed after CTRL was pressed is S or not. If not then set it to false again… For example

Private Declare Function GetKeyboardState _
Lib "user32" (pbKeyState As Byte) As Long

Private Myarray(255) As Byte

Dim Cntrl_Key As Boolean, Vletter_Key As Boolean
Dim OtherLetter As Boolean

Private Sub TextBox1_KeyDown(ByVal KeyCode As MSForms.ReturnInteger, _
ByVal Shift As Integer)
    If KeyCode = 17 Then Cntrl_Key = True
    If KeyCode = 83 Then Vletter_Key = True
    If KeyCode <> 83 And KeyCode <> 17 Then
        OtherLetter = True
    End If
    Call ShowKey
End Sub

Private Sub RefreshKeyState(RefreshState As Boolean)
   If RefreshState Then
      Call GetKeyboardState(Myarray(0))
   End If
End Sub

Private Sub ShowKey()
    '~~> Check for Ctrl + S
    If Cntrl_Key = True And OtherLetter = True Then
        Cntrl_Key = False
    ElseIf Cntrl_Key = True And Vletter_Key = True Then
        '~~> Save Workbook
        ActiveWorkbook.Save
        Cntrl_Key = False
        Vletter_Key = False
    End If
End Sub