IE ToolTip Bug?

I have coded a WinForms marquee scroller program in VB.net/VS2003. Everything works great, but some users have noticed a bug.

When my program is running, IE stops displaying tool tips (TITLE and ALT tags). When my program is closed, they start working again.

I have debugged and went through all the code, and seemed to have found the culprit.

Private Sub tmrTicker_Elapsed(ByVal sender As System.Object, ByVal e As System.Timers.ElapsedEventArgs) Handles tmrTicker.Elapsed
lblMessage.Left = lblMessage.Left – 7
End Sub

That line of code causes the tool tips to disappear. It is also the key line of code that causes my marquee to move from right to left. I have tried making the control a label, textbox, rich text box, and they all did the same thing.

Has anyone else experienced this problem? Is it a bug?

I have tested, and Mozilla allows tool tips when it is running (the TITLE tags at lease, Mozilla doesnÂ’t display ALT tags in general). Also, Windows XP still displays them, and Outlook, etc do to. The only program that doesnÂ’t display tool tips is IE.