[MonoDevelop] Two Dialog Boxes for ProjectService.OpenCombine when file not found

[Scott Ellington]

If I try to use ProjectService.OpenCombine to open a nonexistant file
like:

Runtime.ProjectService.OpenCombine("/path/to/nonexistant/file");

I get two dialog boxes on top of each other telling me the file is not
found.  

The problem seems to be in backgroundLoadCombine:

if (!fileUtilityService.TestFileExists(filename)) {
        monitor.ReportError (string.Format (GettextCatalog.GetString
("File not
found: {0}"), filename), null);
        return;
}

Both fileUtilityService.TestFileExists and monitor.ReportError pop up a
dialog.  

Scott