better navigation of change history

[mariotomo]

What steps will reproduce the problem?

1. edit one existing object
2. select it
3. hit Ctrl-H
4. be happy about the current representation of change data, differences between last changeset and current uncommitted edit
   
5. press the cursor-up key to view the previous change
6. be perplex why it's only showing one changeset, the one before the last.
   
7. press the cursor-down key to go back to the initial representation
8. be perplex why you're now looking at the last changeset, not the difference to your edits
   

What is the expected result?

keep showing a difference between subsequent changes (committed or not).

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

Relative:URL: ^/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2021-09-03 03:12:33 +0200 (Fri, 03 Sep 2021)
Revision:18193
Build-Date:2021-09-03 01:31:19
URL:https://josm.openstreetmap.de/svn/trunk

Identification: JOSM/1.5 (18193 fr) Linux Debian GNU/Linux 10 (buster)
Memory Usage: 415 MB / 1446 MB (111 MB allocated, but free)
Java version: 11.0.12+7-post-Debian-2deb10u1, Debian, OpenJDK 64-Bit Server VM
Look and Feel: javax.swing.plaf.metal.MetalLookAndFeel
Screen: :0.0 1366×768 (scaling 1.00×1.00)
Maximum Screen Size: 1366×768
Best cursor sizes: 16×16→16×16, 32×32→32×32
Environment variable LANG: en_GB.UTF-8
Environment variable LC_ALL: fr_FR.utf8
System property file.encoding: UTF-8
System property sun.jnu.encoding: UTF-8
Locale info: fr_FR
Numbers with default locale: 1234567890 -> 1234567890
Desktop environment: GNOME
Java package: openjdk-11-jre:amd64-11.0.12+7-2~deb10u1
Java ATK Wrapper package: libatk-wrapper-java:all-0.33.3-22
fonts-noto: fonts-noto:all-20181227-1
VM arguments: [-Djava.net.useSystemProxies=true]
Dataset consistency test: No problems found

Plugins:
+ buildings_tools (35756)
+ gridify (1606242219)
+ measurement (35640)
+ reverter (35732)
+ utilsplugin2 (35792)

Map paint styles:
- https://josm.openstreetmap.de/josmfile?page=Styles/Enhanced_Lane_and_Road_Attributes&zip=1

Last errors/warnings:
- 08004.040 W: java.net.ConnectException: Le réseau n'est pas accessible (connect failed)
- 08004.040 E: Connexion au proxy '/192.168.43.1:3128' pour lʼURI 'https://b.tile.openstreetmap.org/17/36350/62404.png' impossible. Lʼexception était: java.net.ConnectException: Le réseau n'est pas accessible (connect failed)
- 08004.040 W: Already here java.net.ConnectException: Le réseau n'est pas accessible (connect failed)
- 08004.041 W: Already here java.net.ConnectException: Le réseau n'est pas accessible (connect failed)
- 08004.041 W: java.net.ConnectException: Le réseau n'est pas accessible (connect failed)
- 08004.041 W: Already here java.net.ConnectException: Le réseau n'est pas accessible (connect failed)
- 08004.041 W: java.net.ConnectException: Le réseau n'est pas accessible (connect failed)
- 09265.470 W: JCS - Silent failure during download: https://tile.openstreetmap.org/15/9142/15546.png
- 10810.918 W: JCS - Silent failure during download: https://tile.openstreetmap.org/19/146330/248707.png
- 20361.508 W: JCS - Silent failure during download: https://tile.openstreetmap.org/19/145927/249209.png

[mariotomo]

step 4

[mariotomo]

step 6

[mariotomo]

step 8

[gaben]

I think it's related to #18697. Notice the version number not bumped in the last row.

[gaben]

Probably regression from #19367.

No, I checked a random old version (r13479) which works the same.