"Select relation" button in relation list doesn't work

[ShadowFoxNixill]

What steps will reproduce the problem?

1. Select some relations in the list
2. Click the "Set the current selection to the list of selected relations" button

What is the expected result?

The current selection in the editor becomes the same as the selected relations in the list

What happens instead?

Absolutely nothing; the previous selection remains intact

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

URL:https://josm.openstreetmap.de/svn/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2019-01-17 18:31:25 +0100 (Thu, 17 Jan 2019)
Build-Date:2019-01-18 02:32:18
Revision:14703
Relative:URL: ^/trunk

Identification: JOSM/1.5 (14703 en) Windows 10 64-Bit
OS Build number: Windows 10 Education 1803 (17134)
Memory Usage: 419 MB / 1820 MB (162 MB allocated, but free)
Java version: 1.8.0_191-b12, Oracle Corporation, Java HotSpot(TM) 64-Bit Server VM
Screen: \Display0 1920x1080, \Display1 1920x1080
Maximum Screen Size: 1920x1080
VM arguments: [-Djava.security.manager, -Djava.security.policy=file:<java.home>\lib\security\javaws.policy, -DtrustProxy=true, -Djnlpx.home=<java.home>\bin, -Djnlpx.origFilenameArg=%UserProfile%\Programs\josm-latest.jnlp, -Djnlpx.remove=false, -Djava.util.Arrays.useLegacyMergeSort=true, -Djnlpx.heapsize=NULL,2048m, -Djnlpx.splashport=60587, -Djnlpx.jvm=<java.home>\bin\javaw.exe]
Dataset consistency test: No problems found

Plugins:
+ continuosDownload (82)
+ utilsplugin2 (34840)

Map paint styles:
+ https://github.com/bastik/mapcss-tools/raw/osm/mapnik2mapcss/osm-results/mapnik.zip

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