According to Open a file in Visual Studio at a specific line number there is a way to get programmatic access to a file with a linenumber, I got that working, great.
Yet, I didn't find any docs for accessing the "Preview Tab feature" of VS2012 with DTE:
Could it be that DTE is now considered deprecated by MS (as not shipping with VS2012) and therefor VS automation reached EOL? That would be a shame. If not, how can I open a file as preview tab instead of normal file tab from e.g. commandline?
