summarizing contents of the Windows Message Queue?

We have a CF.NET 3.5 app that seems to work fine for about 4 hours before a specific bug appears: Once buggy, there is a delay of approx 30 seconds after a mouse click before the corresponding ..._MouseDown event is called. This indicates to me some corruption with the message pump, or possibly an excess amount of stuff in the windows message queue. Can anybody suggest ideas on how to attack this bug, especially since every attempt takes at least 4 hours to test...

Thanks!

PS - loads of unmanaged code in t开发者_如何学Gohe mix, can C++ bugs mess with the .Net message queue?

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Some points to check:

• A method call blocking the message queue.
• An instance of System.Windows.Forms.Timer that was set to some small interval.
• A non-async IO access to some hardware device performed in the GUI thread (irda, serial port, etc)