Created attachment 151612 [details]
Math uses hard-coded colors, which makes it unreadable with, for example, dark backgrounds. The screenshot shows 6.1 left-hand and 6.3 with Jmux' patch using Breeze Dark as Gtk3 theme on LXQt.
Patch is https://gerrit.libreoffice.org/#/c/72795/
You can't see the different mouse-over focus rectangles in the screenshots.
BTW: with current master from today (= at least commit 73f8222109c3091d5119ed47eac5cad4a55b2212), you'll get real focus and key navigation. This was long broken and is handled in bug 65587.
I found the non-filled rectangle more readable then the filled, highlighted one; YMMV. Getting the focus into the ElementsControl is a bit harder, because a click moves focus to the editor. Just select the combo box and tab into it.
So next week is Beta1 of 6.3. Do you know someone additional, who might comment on this? Otherwise I'll merge this to get it into the beta.
Don't see a reason that this could be a failure. So +2 for merging.
Jan-Marek Glogowski committed a patch related to this issue.
It has been pushed to "master":
tdf#125454 SM use theming for element list
It will be available in 6.3.0.
The patch should be included in the daily builds available at
https://dev-builds.libreoffice.org/daily/ in the next 24-48 hours. More
information about daily builds can be found at:
Affected users are encouraged to test the fix and report feedback.