If there is spreadsheet open when I open an .rtf file it opens as a spreadsheet and not a document.
You mean from File - Open? Could not reproduce the problem. Win 7 Pro 64-bit Version: 5.1.0.0.alpha1+ Build ID: d56b125f6c6c18ac40712cefc3cec06530750e15 TinderBox: Win-x86@39, Branch:master, Time: 2015-06-13_07:08:43 Locale: fi-FI (fi_FI)
This is by design, as mentioned here: http://lists.freedesktop.org/archives/libreoffice/2014-July/062540.html