This seems to work for me, although while trying things out I did make the button stop responding. The way it happened was I first built the form. Then I decided to add a ToolStripContainer so I added one, cut the ToolStrip off of the form, and pasted it into the ToolStripContainer.
Unfortunately when you cut and paste a control, Visual Studio removes the association between the control and any existing event handlers that it used to have. If you look way on the right (usually hidden because it's so far to the right) you will see that the Handles clause has been removed.
Check to see if this is what happened to you. If it did, you can add the Handles clause yourself. Or you can double-click on the new button to create a new event handler and copy-and-paste the old code into the new event handler.
Let me know if that was the issue.
Author of "Visual Basic 2005 Programmer's Reference"
Sign up for the free VB
Helper Newsletters at http://www.vb-helper.com/newsletter.html