plugin list starts scrolled down

[Klumbumbus]

What steps will reproduce the problem?

1. open preferences
2. tab plugins

Plugin list is scrolled down.
I checked a random old version (7479) same problem there.

URL:http://josm.openstreetmap.de/svn/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2016-08-16 15:33:43 +0200 (Tue, 16 Aug 2016)
Build-Date:2016-08-17 01:38:24
Revision:10823
Relative:URL: ^/trunk

Identification: JOSM/1.5 (10823 en) Windows 7 32-Bit
Memory Usage: 567 MB / 742 MB (252 MB allocated, but free)
Java version: 1.8.0_101-b13, Oracle Corporation, Java HotSpot(TM) Client VM
VM arguments: [-Djava.security.manager, -Djava.security.policy=file:<java.home>\lib\security\javaws.policy, -DtrustProxy=true, -Djnlpx.home=<java.home>\bin, -Djnlpx.origFilenameArg=C:\Program Files\josm-latest-bla.jnlp, -Djnlpx.remove=true, -Djava.util.Arrays.useLegacyMergeSort=true, -Djnlpx.heapsize=256m,768m, -Djnlpx.splashport=52405, -Djnlpx.jvm=<java.home>\bin\javaw.exe, -Djnlpx.vmargs=LURqYXZhLnV0aWwuQXJyYXlzLnVzZUxlZ2FjeU1lcmdlU29ydD10cnVlAA==]

Plugins:
+ AddrInterpolation (32699)
+ DirectDownload (32699)
+ DirectUpload (32699)
+ HouseNumberTaggingTool (32699)
+ Mapillary (32796)
+ OpeningHoursEditor (32699)
+ apache-commons (32699)
+ apache-http (32699)
+ buildings_tools (32796)
+ editgpx (32699)
+ imagery_offset_db (32796)
+ log4j (32699)
+ measurement (32732)
+ photo_geotagging (32699)
+ reverter (32796)
+ tag2link (32699)
+ tagging-preset-tester (32699)
+ terracer (32699)
+ turnlanes-tagging (1470950886)
+ turnrestrictions (32796)
+ undelete (32699)
+ utilsplugin2 (32815)
+ wikipedia (32796)

Tagging presets:
+ https://josm.openstreetmap.de/josmfile?page=Presets/OneClick&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/StolpersteineLight&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/NewTags&zip=1
+ D:\<user.name>\OSM\JOSMSVN\data\defaultpresets.xml
+ D:\Download\Neu\Presets_Traffic_signs(1).zip
+ https://josm.openstreetmap.de/josmfile?page=Presets/Tagsforobservatories&zip=1

Map paint styles:
+ D:\<user.name>\OSM\JOSMSVN\styles\standard\elemstyles.mapcss
- https://josm.openstreetmap.de/josmfile?page=Styles/HiDPISupport&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Coloured_Streets&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Maxspeed&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Lane_and_Road_Attributes&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/sac_scale&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/ShowID&zip=1
- D:\<user.name>\OSM\eigene styles\PriorityRoad\PriorityRoad_1.0.mapcss
- https://josm.openstreetmap.de/josmfile?page=Styles/LayerChecker&zip=1
+ D:\<user.name>\OSM\TestNew\newicons.mapcss
- https://josm.openstreetmap.de/josmfile?page=Styles/Surface&style&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/ParkingLanes&style&zip=1
- D:\<user.name>\OSM\patches\old MPs\dataquality.mapcss
- https://josm.openstreetmap.de/josmfile?page=Styles/Sidewalks&style&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Cycleways&style&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Osmc&style&zip=1
- https://raw.githubusercontent.com/species/josm-preset-wheelchair/master/sidewalks_kerbs.mapcss
- https://josm.openstreetmap.de/josmfile?page=Styles/LitObjects&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Lit&style&zip=1
- D:\<user.name>\OSM\eigene styles\Tourenplanung.mapcss
- D:\<user.name>\OSM\eigene styles\SpecificBuildingValues\SpecificBuildingValues.mapcss
- https://josm.openstreetmap.de/josmfile?page=Styles/Coloured_buildings&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Modified&zip=1
- https://github.com/bastik/mapcss-tools/raw/osm/mapnik2mapcss/osm-results/mapnik.zip
- http://www.openrailwaymap.org/styles/standard.mapcss
- D:\<user.name>\OSM\eigene styles\area-symbol.zip
- http://www.freietonne.de/ft_icons/josm/FreieTonne_rules_presets_zip.php
- https://josm.openstreetmap.de/josmfile?page=Styles/NewHighwayColors&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/MaxspeedIcons&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/DestinationSignRelation&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/ParkingLanes&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Incline&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/PTStops&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/AdvertisingStyle&zip=1
- https://www.dropbox.com/s/qo3ai47fpv241jf/Styles_Fixme_and_Notes.zip?raw=1

Validator rules:
+ https://raw.githubusercontent.com/stefan-a-bauer/josm-validators/master/mtb.validator.mapcss
+ D:\<user.name>\OSM\TestNew\new.validator.mapcss

Last errors/warnings:
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: Unsaved changes - <html>The relation has been changed.<br><br>Do you want to save your changes?</html>
- W: Old style SideButton usage for action org.openstreetmap.josm.plugins.mapillary.gui.MapillaryChangesetDialog$SubmitAction@1804273

[Don-vip]

In 10828/josm:

fix #13368 - plugin list starts scrolled down