Quote:
Printpreviewcontrol not showing document. No errors.
Start by not just swallowing exceptions:
Try
Select Case TabControlMAIN.SelectedIndex
...
End Select
Catch ex As Exception
End Try
If you get an error in that code, you throw it away and never know it occurred.
At a minimum, log the error to the debug console or a log file so that you can investigate what it was and why it occurred.
When you specifically discard any exceptions, you will get "No errors" - but stuff still won't work if there is a problem only you will have no idea why!