Advanced

DataObject

A holding area for formatted text data used in transfer operations. Also holds a list of formats corresponding to the pieces of text stored in the DataObject.

MSForms.DataObject 

A DataObject can contain one piece of text for the Clipboard text format, and one piece of text for each additional text format, such as custom and user-defined formats.
A DataObject is distinct from the Clipboard.
A DataObject supports commands that involve the Clipboard and drag-and-drop actions for text.
A DataObject supports commands that involve the Clipboard and drag-and-drop actions for text. When you start an operation involving the Clipboard (such as GetText) or a drag-and-drop operation, the data involved in that operation is moved to a DataObject.

The DataObject works like the Clipboard. If you copy a text string to a DataObject, the DataObject stores the text string.
If you copy a second string of the same format to the DataObject, the DataObject discards the first text string and stores a copy of the second string.
It stores one piece of text of a specified format and keeps the text from the most recent operation.

Dim oDataObject As MSForms.DataObject 
oDataObject = New MSForms.DataObject 
oDataObject.SetText "some text" 
oDataObject.PutInClipboard 
oDataObject.GetFromClipboard 

Data Binding

RowSource is a table/query for a ComboBox or ListBox.
ControlSource is a field to which a control is bound.

Row Source - It is used to fetch the data to the control for which the property is set.
Control Source - If more than one field/column is retrieved in the Row Source property

The Control Source, as was mentioned by Rural Guy, is the property of a control which is normally set to a field name that exists in the form's Record Source (table, query or select statement). You can type a formula in there too but then it will not update a table. It has to be "bound" to a field from the table, query, or Select statement so that Access knows where to store or edit the data for that control.

Shortcut Menus

Const PopUpName As String "MyPopUpMenu" 

Sub DeletePopupMenu 
   CommandBars(PopUpName).Delete 
End Sub 

Sub CreatePopupMenu 
Dim cb As CommandBar 
Dim cbp As CommandBarPopup 

   Set cb = CommandBars.Add(PopUpName, msoBarPopup, False, True) 
   With cb 
      With .Controls.Add(Type:=msoControlButton) 
         .OnAction = "" 
         .FaceId = 10 
         .Caption = "" 
         .ToolTipText = "" 
       End With 

      Set cbp = .Controls.Add(Type:=msoControlPopul 
      With cbp 
         .BeginGroup = True 
          .Caption = "sub menu" 
           With .Controls.Add(Type:=msoControlButton) 

           End With 
           Set cbp = Nothing 
      End With 
   End With 
Set cb = Nothing 
End Sub 

Sub DisplayPopUp 
   Application.CommandBars(PopUpName).ShowPopup 
End Sub 

In the Userform code module

Private Sub UserForm_MouseMove(byVal Button As Integer, ByVal Shift As Integer, ByVal X As Single, ByVal Y As Single) 
   if Button = 2 Then 
'number 2 is the right mouse button
      Call DisplayPopUp 
   End If 
End Sub 

Creating Dynamically

Creating userforms dynamically
adding controls
adding the event subroutines
moving and sizing controls

Importing a Userform
The quickest way to add a userform to a project is to just import it from a saved file.

Dim objVBC As VBComponent 
Set objVBC = Application.VBE.ActiveVBProject.VBComponents.Import("MyForm.frm") 

The advantage of doing it through code is that the userform can be given a size appropriate to the user's screen resolution and size, and its controls positioned correctly.
Windows API call to freeze a window.
Private Declare Function LockWindowUpdate Lib "User32" (ByVal hwndLock As Long) As Long
Application.ScreenUpdating does not affect the VBE
You should use the above API function to freeze and unfreeze the window accordingly.
It is a good idea to leave 6 points between controls and between a control and the edge of the userform.
Freeze the VBE window
The HWnd property is a hidden property of the MainWindow object.

LockWindowUpdate Application.VBE.MainWindow.HWnd 

Add a new userform

Set objVBC = Application.VBE.ActiveVBProject.VBComponents.Add(vbext_ct_MSForm) 

set the height and width

objVBC.Properties("Width") = Application.UsableWidth * 2 / 3 
objVBC.Properties("Height") = Application.UsableHeight * 2 / 3 

Adding controls

Dim objFrmDesign As ?? 
Dim objControl As ?? 

Set objFrmDesign = objVBC.Designer 

   Set objControl = objFrmDesign.Controls.Add("Forms.CommandButton.1"),"bnOK") 
   objControl.Caption = "OK" 
   objControl.Default = True 
   objControl.Height = 20 
   objControl.Width = 20 

The name of the control to add can be found by adding a control from the Control Toolbox to a worksheet and then examining the EMBED function.
Add the references "Microsoft Forms 2.0 Object Library"
Add the references "Microsoft Visual Basic for Applications Extensibility 5.3"

Dim obVBE As VBIDE.VBE 
Dim frm1 As VBIDE.VBCompionent 
Dim frm2 As MsForms.Userform 
Set obVBE = Application.VBE 
Set frm1 = obVBE.ActiveVBProject.VBComponets.Add(vbext_ct_MSForm) 
Dim cmd1 As MsForms.Control 
With frm1 
   .Properties("Height") = 280 
End With 
With frm2 
   .Font.Name = "Tahoma" 
End With 
Set cmd1 = frm2.Controls.Add("Forms.CommandButton.1","cmbButton1")