Printing Children

In the Click event of the parent menu (the one at the top, where you click to bring up the dropdown menu containing Print), add code to check the MdiChildren collection. If its length is 0, you know to disable the Print item:

Private Sub mnuFile_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles mnuFile.Click
mnuPrint.Enabled = (Me.MdiChildren.Length > 0)
End Sub

That should do it.

Except, of course (for those reading this later), it didn't--you need to use the Popup event, not the Click event, to get this to work correctly. (Just updating the thread for posterity... <g>)