JabRef 5.2--2020-10-15--13a80ba
Windows 10 10.0 amd64
Java 14.0.2

• Mandatory: I have tested the latest development version from http://builds.jabref.org/master/ and the problem persists

The entry preview window does not load my customized visual theme as the rest of the GUI. I loaded my customized visual theme (copy of the source Dark.css file) but was not able to change colors of the preview textarea to match the dark theme of the rest of the GUI. Instead selecting "Dark theme" from Options > Appearance correctly makes the background dark.

Steps to reproduce the behavior:

1. From the source tree take the Dark.css file
2. Open Options > Appearance and select this file as "Custom theme"
3. Restart JabRef and double click on an entry. The preview textarea has a white background
4. If you select instead "Dark theme" the background is correctly dark.

I suspect the problem is in file: jabref-master\src\main\java\org\jabref\gui\preview\PreviewViewer.java where I don’t see any reference to theme in JS_HIGHLIGHT_FUNCTION definition or in setPreviewText() function, so the #previewBody block in Dark.css has no effect.