Indication of choosen preference category vanishes [patch]

[skyper]

What steps will reproduce the problem?

1. Open preferences
2. Watch the blue background of the category on the left side
3. enable/disable expert mode or click on a box on the right side

What is the expected result?

The blue background on the left stays

What happens instead?

The background vanishes

Please provide any additional information below. Attach a screenshot if possible.

I've tested with Metal and there the background stays, so I expect this to be a problem with the theme.

Relative:URL: ^/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2020-11-14 16:31:36 +0100 (Sat, 14 Nov 2020)
Revision:17310
Build-Date:2020-11-15 02:30:52
URL:https://josm.openstreetmap.de/svn/trunk

Identification: JOSM/1.5 (17310 en) Linux Debian GNU/Linux 10 (buster)
Java version: 11.0.9+11-post-Debian-1deb10u1, Debian, OpenJDK 64-Bit Server VM
Look and Feel: com.formdev.flatlaf.FlatDarculaLaf

Plugins:
+ flatlaf (35589)

[DevCharly]

The "bluish" tab background indicates only that the JTabbedPane has focus.
Selected tab is only highlighted by the thick blue line at the right side of the tabs.

This is normal behavior, but I understand that it is hard to recognize the selected tab in the
Preferences dialog.

Luckily it is possible to tell FlatLaf to use another color for selected tabs.
Patch attachment:OSM-FlatLaf-plugin-tabbedpane-selection.diff​​ makes the selected tabs slightly darker.
This affects all tabbed panes in JSOM.

[skyper]

Thanks, never realized the blue line as indicator. Thought it is a scroll bar.

Guess it will look similar to the vertical tabs on top in FlatLaf-HideableTabbedPane-fixed.png​. Nice.

[DevCharly]

In 35697/osm:

see #20086 - Indication of choosen preference category vanishes

use different background color for selected tab in all tabbed panes

[skyper]

works now, thanks.

Only when en-/disabling Expert Mode the background color changes from a light blue to a dark grey but that is no problem for my eyes.

Fixed?

[DevCharly]

Only when en-/disabling Expert Mode the background color on the left side changes from a light blue to a dark grey but that is no problem for my eyes.

This normal. The selected tab is light blue if the tabbedpane has focus.
When you click the "Expert mode" checkbox, the tabbedpane looses focus.

Here is a screenshot that shows the two colors used for selected tab background: