Event handling for TabControl

You need to handle the MouseDown event for the TabControl, and check to see which tab contained the the mouse cursor. This is done by checking the bounding rectangle of each tab (the corresponding tab, not the TabPage itself). Here's some modified code that should help. When you press a L or R mouse button over a tab, a MsgBox will give you the proper TabPage.

Public Class Form1

  Friend WithEvents MaxTab As TabControl

  Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
    ''dataentry
    MaxTab = New TabControl
    MaxTab.Name = "tabd"
    MaxTab.Top = 1
    MaxTab.Size = New System.Drawing.Size(Me.Width - 15, Me.Height - 80)
    MaxTab.TabPages.Add("dTAB1")
    MaxTab.TabPages.Add("dTAB2")
    AddHandler MaxTab.MouseDown, AddressOf tabs_MouseDown

    Me.Controls.Add(MaxTab)

    ''Report
    MaxTab = New TabControl
    MaxTab.Name = "tabr"
    MaxTab.Top = 1
    MaxTab.Size = New System.Drawing.Size(Me.Width - 15, Me.Height - 80)
    MaxTab.TabPages.Add("rTAB1")
    MaxTab.TabPages.Add("rTAB2")
    Me.Controls.Add(MaxTab)

    Me.Controls("tabr").Visible = False
    Me.MaxTab.Refresh()
  End Sub

'here's where you get the tab page...
  Private Sub tabs_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles MaxTab.MouseDown

    Dim r As Rectangle
    Dim ll As Integer

    For ll = 0 To MaxTab.TabPages.Count - 1
      r = MaxTab.GetTabRect(ll)
      If e.X >= r.Left And e.X <= r.Right And e.Y >= r.Top And e.Y <= r.Bottom Then
        MsgBox(MaxTab.TabPages(ll).Text)
        Exit For
      End If
    Next
  End Sub

End Class