changeset manager: No download area after downloading modified objects

[skyper]

What steps will reproduce the problem?

1. open changeset manager
2. enter a changeset number (​78281753) at the top and download changeset information
3. select changeset
4. download modified objects

What is the expected result?

Download area is shown. As there is no certainty that the data is complete, there should be no download area and all striped in background.

What happens instead?

No download area calculated and no strips

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

Relative:URL: ^/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2019-12-11 01:40:30 +0100 (Wed, 11 Dec 2019)
Revision:15582
Build-Date:2019-12-11 02:30:55
URL:https://josm.openstreetmap.de/svn/trunk

Identification: JOSM/1.5 (15582 en) Linux Debian GNU/Linux 10 (buster)
Memory Usage: 349 MB / 964 MB (151 MB allocated, but free)
Java version: 11.0.5+10-post-Debian-1deb10u1, Debian, OpenJDK 64-Bit Server VM
Java package: openjdk-11-jre:amd64-11.0.5+10-1~deb10u1
Java ATK Wrapper package: libatk-wrapper-java:all-0.33.3-22
libcommons-compress-java: libcommons-compress-java:all-1.18-2
libcommons-logging-java: libcommons-logging-java:all-1.2-2
fonts-noto: fonts-noto:all-20181227-1
Dataset consistency test: No problems found

Last errors/warnings:
- W: No configuration settings found.  Using hardcoded default values for all pools.