Advanced Preferences could not export selected items if they have default values

[mdk]

What steps will reproduce the problem?

1. Select some values in Advanced Preferences
2. Export Selected Items
3. Open Export file in an editor

What is the expected result?

All selected preference items results in a line in the export file.

What happens instead?

Only items with non default values are exported (yellow backgrond in Preferences).
Items with default values (white background) are ignored.

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

How can I export a default preference value? What if I want to have two files for HiDPI Scaling 2.0 and 1.0 for quickly change between both settings? It's not possible to export the 1.0 scaling, because these items are missing in such a fille. I have different JOSM installations. How can I export the reset of a preference item on one installation and import (the reset) in an other one?

I see two possible solutions:

1. Don't ignore and export the default value.
2. Export the item not with value= but with something like reset=true.

Relative:URL: ^/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2020-09-19 20:27:13 +0200 (Sat, 19 Sep 2020)
Revision:17046
Build-Date:2020-09-20 01:30:51
URL:https://josm.openstreetmap.de/svn/trunk

Identification: JOSM/1.5 (17046 en) Linux Ubuntu 20.04.1 LTS
Memory Usage: 329 MB / 1980 MB (121 MB allocated, but free)
Java version: 14.0.1+7-Ubuntu-1ubuntu1, Private Build, OpenJDK 64-Bit Server VM
Look and Feel: javax.swing.plaf.metal.MetalLookAndFeel
Screen: :0.0 3840x2160 (scaling 1.0x1.0)
Maximum Screen Size: 3840x2160
Best cursor sizes: 16x16 -> 16x16, 32x32 -> 32x32
Desktop environment: ubuntu:GNOME
Java ATK Wrapper package: libatk-wrapper-java:all-0.37.1-1
libcommons-compress-java: libcommons-compress-java:all-1.19-1
libcommons-logging-java: libcommons-logging-java:all-1.2-2
fonts-noto: fonts-noto:-
VM arguments: [--add-modules=java.scripting,java.sql, -Djosm.restart=true, -Djosm.dir.name=JOSM-latest, -Djava.net.useSystemProxies=true]

Plugins:
+ ColumbusCSV (35405)
+ FastDraw (35499)
+ HouseNumberTaggingTool (35508)
+ OpeningHoursEditor (35414)
+ RoadSigns (35510)
+ SimplifyArea (35405)
+ buildings_tools (35500)
+ contourmerge (v0.1.6)
+ imagery-xml-bounds (35546)
+ imagery_offset_db (35405)
+ pbf (35446)
+ poly (35248)
+ public_transport (35405)
+ reltoolbox (35529)
+ reverter (35499)
+ terracer (35499)
+ turnrestrictions (35515)
+ utilsplugin2 (35487)
+ wikipedia (1.1.4)

Tagging presets:
+ https://josm.openstreetmap.de/josmfile?page=Presets/OneClick&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/LaneAttributes&preset&zip=1

Map paint styles:
+ https://josm.openstreetmap.de/josmfile?page=Styles/Lane_and_Road_Attributes&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Styles/Maxspeed&style&zip=1