<p>I have a Windows Form app with a TabControl. One of the TabPages in the TabControl contains a ToolStrip. Frequently, the Windows Form designer will spontaneously set the Visible property of the Toolstrip to False. To get the toolstrip to reappear in my form, I have to manually find the control and set the property back to True. It's really annoying.</p>

<p>Does anyone know why this happens, or how to stop it? I've tried setting the minimum height of the control to a non-zero value, but that has no effect.</p>

<p>I'm using VS2008, VB.NET and the .Net framework 2.0, however I've struggled with this problem in VS2005 too, in several different applications.</p>

I may have found a workaround for this.
My ToolStrip was placed directly on the TabPage, docked to Top. However, I found
a thread on Microsoft Connect
that described the same problem when the ToolStrip was in a ToolStripContainer on the TabPage. That problem was observed in a release candidate of VS2005, but supposedly fixed by Microsoft in September 2006.
As such, I changed my code to put the ToolStrip inside a ToolStripContainer, and now I am unable to reproduce the problem.