I've got something weird going on with Visual Studio. I have Office 2007 installed as well as both Visual Studio 2005 and Visual Studio 2008. I can develop VSTO solutions for Office 2003 using VS2005 without problem. I can also create a VSTO Word add-in for Word 2003 using VS2008 and .NET 3.5, build it and deploy it without problem. However as soon as I close my Word 2003 add-in solution, when I next try to open it using VS2008, I get the Visual Studio Conversion Wizard popping up saying the solution was created in a different version of Visual Studio (which it was not). If I run the wizard, it changes the add-in project to use VSTO 3 and changes the PIA references to use the 2007 PIAs.
Any ideas (other than developing it using VS2005 and .NET 2)?