Wrong behaviour of sub/superscript switching

[texnic]

1. Create a new document.
2. Put letter "a". With default settings you get in SVG:

font-size:30px;font-style:normal;font-weight:normal;line-height:125%;letter-spacing:0px;word-spacing:0px;fill:#000000;fill-opacity:1;stroke:none;font-family:Sans

3. Put the cursur to the rught of this letter and press the subscript tool-button. The letter size becomes 7.8, and it's subscripted:

font-size:65%;font-style:normal;font-weight:normal;line-height:125%;letter-spacing:0px;word-spacing:0px;fill:#000000;fill-opacity:1;stroke:none;font-family:Sans;baseline-shift:sub

4. Press the subscript tool-button again. The letter is no more subscripted, but the size is 12:

font-size:;font-style:normal;font-weight:normal;line-height:125%;letter-spacing:0px;word-spacing:0px;fill:#000000;fill-opacity:1;stroke:none;font-family:Sans;baseline-shift:baseline

[Patrick Storz (ede123)]

Still reproduces in
- Inkscape 0.92.2pre0 (f9bf460709, 2017-07-30)
- Inkscape 0.92+devel (d0390b9f4f, 2017-07-31)

The "font-size:" attribute is emptied and the previous text size is lost.

[Nathan Lee (nathan.lee)]

Hi - thanks for reporting this bug, I've manually migrated it to Inkscape's new
bug tracker on GitLab, and closed it here.

Please feel free to file new bugs about the issues you're seeing at
http://inkscape.org/report.

Moved to: https://gitlab.com/inkscape/inbox/-/issues/4166