Confirmed on qa@fr mailing list.

assign to type detection maintainer :)

was this an intentional change, iirc the same thing happens
for html files, open it in the application that the user already
has open if that supports it?

Yes, this is an intended behavior, for html, plain text, and rtf files.

Migrating Whiteboard tags to Keywords: (rtf_filter -> filter:rtf)
[NinjaEdit]

*** Bug 146953 has been marked as a duplicate of this bug. ***

Combining related quotes, in addition to Kohei's comment 3.

Maxim Monastirsky in bug 65017 comment #19 (relates to this issue):
> This is the desired result, since Calc has its own rtf filter [1]. And the
> type detection framework honors the DocumentService by design [2].
> 
> [1] http://opengrok.libreoffice.org/xref/core/sc/source/filter/rtf/
> [2]
> http://opengrok.libreoffice.org/xref/core/filter/source/config/cache/
> typedetection.cxx#481

Eike Rathke in bug 146953 comment #10:
> If both modules/apps offer a filter for a file format then the currently
> active one is used. Maybe unless the file type is selected in the file
> picker.

For the record - I believe it is bad UX (the user-perceived randomness of where an RTF file opens)

(In reply to Thorsten Behrens (allotropia) from comment #7)

I don't quite see why.

Of course, LibreOffice internally is a single program. However, it offers separate windows for different documents. When a user opens some spreadsheet, it shows Calc UI for them. It is not much different UX from e.g. MS Office, where it opens spreadsheets in Excel.

Then you have Calc open, and you open a document from it. If you did that in MS Excel, you wouldn't be surprised that Excel tried to open it; why have different expectations for Calc?

OTOH, when you have Calc open, and try to open RTF from file manager (as opposed to "from Calc"), it opens in Writer. Again, not different to what MS Office users are accustomed to.

Possibly one related problem is that we have no separate Start Center accessible *when documents are open*, that could be the neutral starting point, allowing users to open "from LibreOffice" when you only have a single spreadsheet document open in it; but it's a different bug 77590.

(In reply to Mike Kaganski from comment #8)
> I don't quite see why.

Problem in inconsistency of this behavior, IMO

If we compare to Excel, we can see that Excel:
 a. opens requested doc if it is known spreadsheet format (xlxs, ods, ...)
 b. tries to import requested doc (txt, rtf, ...)
 c. refuses to open (doc, docx, ...). 

And this is quite expected behavior from user point of view: user can see that he is trying to open document explicitly with Excel. As a user I feel Excel as a standalone application:
- it does not have common launcher with other office docs, like in LO
- it does not tries to open unknown to Excel documents, like in LO
- it have separate list of recent documents, like in LO

In case of LO there is a different situation. Calc in this case:
 a. opens requested doc, if it is known spreadsheet format (xlxs, ods, ...)
 b. tries to import requested doc (txt, rtf, ...)
 c. tries to open document with other LO apps: Writer, Impress, etc (doc, docx, image formats, ...)
 d. reports corrupted file with proposal to repair it (other random binary files)

So I see that Calc (unlike Excel) behaves as a part of bigger office suite, proposing different apps for different files. And this is a confusion point: as a user I can't predict how some arbitrary file will be opened from inside LO. In one case it is using one app, in another - different one.

If we want to have Calc as an "independent app" similar to Excel, than we should not try to open documents with other apps, have own recent documents list, etc. This is not a case, IMHO.

For what it's worth, my personal opinion is the same as Mike.  Since RTF is an app-independent format with different apps having the capability to open it, it seems natural to me that the current application should take the priority.

Having said this, since you all claim this to be an UX issue, and this project has an official UX channel, we should perhaps let them decide, rather than having the developers argue over what is "right".  When it comes to these issues, I don't think all sides will converge to a single view; so adding yet another configuration option is certainly an option.  To me this is one of those odd cases where different users with different backgrounds have totally different and strong viewpoints.

Just my 2 cents.