title: Dialog MessageBox sometimes hidden behind the main form
body: <p>Some of our non-technical users are having problems where a dialog MessageBox in our application can sometimes be displayed behind the main form and the application does not accept any input until the messagebox (which they can't see) is dismissed.</p>
  
  <p>The application is written in C# and the message boxes are standard eg the code can be as simple as MessageBox.Show(message, caption) and the messageboxes can be created by the main UI thread (ie not some background thread). The Application does not have to be run full-screen, but 90% of our users do run it full-screen.</p>
  
  <p>Most of the time ((maybe > 99%) the messageboxes display correctly and I have never managed to see how it goes wrong, but I have seen a machine when it has gone wrong. </p>
  
  <p>One thing I did notice is that if you have an application which displays a dialog box, then when you look at your taskmanager, you normal only see one entry in the application list. Whenever the messagebox is hidden, you will see two entries, one for the main application and another entry for this message box.</p>
  
  <p>It is easy enough to fix the problem once you know what has happened, but some of our non-technical users are confused by it and end up switching off their computers. (And the ones who are using Remote Desktop are even more confused when that doesn't solve the problem).</p>
  
  <p>I do not think it is related to the operating system as I have seen it happen in Vista and have been told it also happens in a terminal session on a Windows 2003 server.</p>
  
  <p>Does anything know why this is happening and more importantly if anything can be done to avoid it?</p>