try placing the same code in the current event of the form
Private Sub Form_Current()
Select Case Me.cboWorkCategory.Column(1)
Case "CLIENT RATES", "PHARMACY RATES", "COPAY", "ADVANTAGE 90", "DAW", "ACCUMULATIONS", "NEW PLAN - COPIED/TEMPLATE", "PANELS", "NEW PLAN", "SPECIALTY", "NON-ELIGIBILITY PLAN"
Me.ROUTING_MCO_FIFO.Controls("cboMCOClaimsMonitor").Enabled = True
Me.ROUTING_COMMERCIAL_FIFO.Controls("cboCOMClaimsMonitor").Enabled = True
Case Else
Me.ROUTING_MCO_FIFO.Controls("cboMCOClaimsMonitor").Enabled = False
Me.ROUTING_COMMERCIAL_FIFO.Controls("cboCOMClaimsMonitor").Enabled = False
End Select
End Sub