How do I attach correctly?

[Nobodo]

I really don't like having imported items as their own listing in the Data Explorer, and do not want to view any imported items within UR itself.
I just want to import them and see them as icons that I can click on to open in the external application (basically I want to store word documents, stored procedures, spreadsheets, etc. inside the info item that has information about them, and never view these documents within UR).

I find that I am able to do that by dragging and dropping items from Windows Explorer to an existing item (see image).
However, some file types refuse to do that. They display internally no matter what I do (again, see image).

Also i find that often dragging and dropping an excel spreadsheet to an open item will initially display the spreadsheet internally, then causes UR to completely lock up. I have to close UR, restart it, then remove the .xls or .xlsx. Even after restarting, if I do not remove the .xls that is displaying embedded within an item, eventually UR is going to lock up again. Sometimes I get this lockup when dragging/dropping other types of files to existing items also. I'm not talking about huge files, either. These are files way under 100k in size.

I've tried changing import options, browser option, editor options, dropping them on different types of info items, everything I can find to get these files to stop displaying internally and stop causing a complete lockup of the application.

Is what I want to do here possible? If not, why does it work fine for some file extensions but not for others?

thanks,
Mark.