Created attachment 52011 [details]
RTF formatted testcase

When using superscripts and subscripts in a text, the font is resized in the UI to honor the linespacing. The problem arises when using subscripts and superscripts in the text and saving the file as RTF. One would expect that what we see in the UI is somewhat translated into the saved file so it can be reproduced when the file is reopened. The actual behavior on the saved file differs in such way that the characters super/subscripted are the same size as the font, shifted up. That causes the file not being reproductible even in LibreOffice.

Steps to reproduce:

1. Open a new Writer document or any existent document in any format.
2. Type in some text
3. Select a part of the text (just a few characters) and format those as superscript or subscript.
4. Save the document in RTF format.
5. Close the file
6. Reopen the same file.

What I expect: sub/superscripts resized so they don't add line spacing or fall out the fixed linespace.

What actually happens: The sub/superscripts are not resized, they are the same size as the main text just shifted up half line. One of two format annoyance follows: The line spacing gets bigger for just that line, or the text characters are cut-off (unreadable for the user) when the line spacing is fixed.

This issue is independent of the distribution (I'm assuming that based on two tests on different distributions, Arch and Ubuntu). Also is independent on the font used.
The worst problem is that you only notice it when reopening the file, that means that LibreOffice doesn't work WYSIWYG on that, you will see the right formatting on the screen but is not saved that way.

I'm attaching a testcase.