Very simple example :

VB Code:
  1. ' ON GOT FOCUS EVENT ON CERTAIN CONTROLS

  2.  
  3. Function YELLOWGOTFOCUS(GETCONTROL As Control)

  4.  
  5.     On Error Resume Next

  6.     

  7.     If TypeOf GETCONTROL Is TextBox Then

  8.     

  9.         GETCONTROL.BackColor = vbYellow

  10.         

  11.         GETCONTROL.ForeColor = vbRed

  12.         

  13.         GETCONTROL.SelStart = 0

  14.         

  15.         GETCONTROL.SelLength = Len(GETCONTROL)

  16.             

  17.     ElseIf TypeOf GETCONTROL Is ComboBox Then

  18.     

  19.         GETCONTROL.BackColor = vbYellow

  20.         

  21.         GETCONTROL.ForeColor = vbRed

  22.         

  23.     End If

  24.  
  25. End Function

  26.  
  27. ' ON LOST FOCUS OF CERTAIN CONTROLS

  28.  
  29. Function WHITELOSTFOCUS(GETCONTROL As Control)

  30.  
  31.     If TypeOf GETCONTROL Is TextBox Then

  32.     

  33.         GETCONTROL.BackColor = vbWhite

  34.         

  35.         GETCONTROL.ForeColor = vbBlack

  36.         

  37.     ElseIf TypeOf GETCONTROL Is ComboBox Then

  38.     

  39.         GETCONTROL.BackColor = vbWhite

  40.         

  41.         GETCONTROL.ForeColor = vbBlack

  42.             

  43.     End If

  44.  
  45. End Function

If you add this code to a module, you can access from anywhere inside your project...