UserForm in POS blocks client tab

First, the f.CarregaEntidades (Me.DocumentoVenda.Entidade) line does not make sense.

The problem may be that the userform is being called "Modal"

Place ShowModal = False

And try putting:

DoEvents
Load UserForm1
UserForm1.CarregaEntidades (cliente)
UserForm1.Show vbModeless

@Manuel Quelhas answer is fine, it would only add the fact that in the POS the client card is modal and as such its window automatically goes down. To avoid this is to use windows API:

Const HWND_TOPMOST = -1
Const HWND_NOTOPMOST = -2
Const SWP_NOSIZE = &H1
Const SWP_NOMOVE = &H2
Const SWP_NOACTIVATE = &H10
Const SWP_SHOWWINDOW = &H40

Private Declare Sub SetWindowPos Lib "user32" (ByVal hWnd As Long, ByVal hWndInsertAfter As Long, ByVal X As Long, ByVal Y As Long, ByVal cx As Long, ByVal cy As Long, ByVal wFlags As Long)
Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long

Private Sub FichaClientes_DepoisDeGravar(ByVal Cliente As String)
Dim f As New UserForm1
Dim hWnd As Long

    f.Show
    hWnd = FindWindow("ThunderDFrame", f.Caption)
    SetWindowPos hWnd, HWND_TOPMOST, 0, 0, 0, 0, SWP_NOACTIVATE Or SWP_SHOWWINDOW Or SWP_NOMOVE Or SWP_NOSIZE

    Exit Sub

erro:
    MsgBox Err.Description
End Sub

I noticed However, the form I'm opening is not modal and portal does not suspend execution of the previous event. In this case, it may not be the most appropriate because I lose the visual reference of the client in question since, as I do not suspect the event, the form of the customer card is cleaned.

I'll try to open the same form with a specific key in the sales editor

Thanks for the help