The test plan:

• doesn't include steps for testing clean install/upgrade
• doesn't work (I've tried to do as written in test plan and problem is still there)

The rINP15434 commit can be used as reference, when performing requested fixes.

Typical workflow, when making CSS-related changes:

1. make a change to the /core/admin_templates/incs/style_template.css file
2. go to /core/admin_templates/incs directory
3. create patch using following command: svn diff style_template.css > x.patch
4. open /core/install/upgrades.css file for editing (not in editor, that strips whitespaces on empty lines)
5. add standard version comment (e.g. # ===== v 5.2.2 =====) if missing
6. put contents of above created patch file after it and save changes
7. copy over contents of styke_template.css file (except file comment) into the primary skin
8. export primary skin record (e.g. via phpMyAdmin) as INSERT INTO statement
9. replace existing INSERT INTO statement into Skins table in the /core/install/install_data.sql file (replace actual ID with DEFAULT keyword)
10. perform clean install to confirm, that skin contains correct CSS
11. perform install of previous In-Portal version and upgrade to current one to confirm, that skin was patched to include correct CSS