"Tile zoom offset" doesn't have any effect on macOS in HiDPI mode

[Stereo]

What steps will reproduce the problem?

1. Under Imagery preferences / Tab Settings / Tiles zoom offset, set a zoom offset of 1 or 2, as described on https://josm.openstreetmap.de/wiki/Help/HiDPISupport
2. Restart JOSM
3. Create a new layer
4. Add an imagery layer

What is the expected result?

Imagery layer is displayed in high dpi mode

What happens instead?

No visible difference

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

See ticket, difference between the lat/lon (good) and the imagery (bad)

URL:https://josm.openstreetmap.de/svn/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2020-02-01 01:10:57 +0100 (Sat, 01 Feb 2020)
Build-Date:2020-02-01 00:12:46
Revision:15806
Relative:URL: ^/trunk

Identification: JOSM/1.5 (15806 en_GB) Mac OS X 10.15.2
OS Build number: Mac OS X 10.15.2 (19C57)
Memory Usage: 886 MB / 1820 MB (527 MB allocated, but free)
Java version: 1.8.0_241-b07, Oracle Corporation, Java HotSpot(TM) 64-Bit Server VM
Screen: Display 69733632 1680x1050
Maximum Screen Size: 1680x1050
VM arguments: [-Djava.library.path=/Applications/JOSM.app/Contents/MacOS, -DLibraryDirectory=${HOME}/Library, -DDocumentsDirectory=${HOME}/Documents, -DApplicationSupportDirectory=${HOME}/Library/Application Support, -DCachesDirectory=${HOME}/Library/Caches, -DApplicationDirectory=${HOME}/Applications, -DAutosavedInformationDirectory=${HOME}/Library/Autosave Information, -DDesktopDirectory=${HOME}/Desktop, -DDownloadsDirectory=${HOME}/Downloads, -DMoviesDirectory=${HOME}/Movies, -DMusicDirectory=${HOME}/Music, -DPicturesDirectory=${HOME}/Pictures, -DSharedPublicDirectory=${HOME}/Public, -DSystemLibraryDirectory=/Library, -DSystemApplicationSupportDirectory=/Library/Application Support, -DSystemCachesDirectory=/Library/Caches, -DSystemApplicationDirectory=/Applications, -DSystemUserDirectory=/Users, -DUserHome=${HOME}, -DSandboxEnabled=true, -DLaunchModifierFlags=0, -DLaunchModifierFlagCapsLock=false, -DLaunchModifierFlagShift=false, -DLaunchModifierFlagControl=false, -DLaunchModifierFlagOption=false, -DLaunchModifierFlagCommand=false, -DLaunchModifierFlagNumericPad=false, -DLaunchModifierFlagHelp=false, -DLaunchModifierFlagFunction=false, -Dapple.laf.useScreenMenuBar=true, -Dcom.apple.macos.use-file-dialog-packages=true, -Dcom.apple.macos.useScreenMenuBar=true, -Dcom.apple.mrj.application.apple.menu.about.name=JOSM, -Dcom.apple.smallTabs=true]
Dataset consistency test: No problems found

Plugins:
+ AddrInterpolation (35248)
+ CommandLine (35297)
+ ImportImagePlugin (35248)
+ Mapillary (1.5.20)
+ MovementAlert (1511141840)
+ OpeningHoursEditor (35250)
+ PicLayer (35313)
+ ShapeTools (1240)
+ alignways (35248)
+ apache-commons (35092)
+ apache-http (35092)
+ areaselector (359)
+ austriaaddresshelper (57)
+ buildings_tools (35248)
+ changeset-viewer (22)
+ conflation (0.6.4)
+ continuosDownload (91)
+ contourmerge (v0.1.6)
+ ejml (35122)
+ geotools (35169)
+ jaxb (35092)
+ jna (35092)
+ jogl (1.2.3)
+ jts (35122)
+ log4j (35092)
+ opendata (35313)
+ openqa (0.1.9)
+ public_transport (35313)
+ reltoolbox (35313)
+ reverter (35313)
+ rex (53)
+ splinex (35248)
+ terracer (35325)
+ todo (30306)
+ turnrestrictions (35313)
+ undelete (35313)
+ utilsplugin2 (35248)
+ wikipedia (1.1.3)

Tagging presets:
+ https://josm.openstreetmap.de/josmfile?page=Presets/NewTags&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/BicycleJunction&preset&zip=1
+ http://osmtools.de/josm/steps.xml
+ https://josm.openstreetmap.de/josmfile?page=Presets/Historic_Stone&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/LaneAttributes&preset&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/Towers&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/Golf_Course&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/PublicTransportOneClick&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/Bus_lanes&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/Heritage&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/Historical_Objects&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/public_bookcase&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/Stolpersteine&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/BuildingPreset&zip=1
+ https://gitlab.com/k127/josm-presets/raw/master/diplomatic.xml

Map paint styles:
- https://josm.openstreetmap.de/josmfile?page=Styles/Lit&style&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/ParkingLanes&style&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Surface&style&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Maxspeed&style&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Modified&style&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/LessObtrusiveNodes&style&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/AddressValidator&style&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Noname&style&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Power&style&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Surface-DataEntry&style&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/PowerMapping&style&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Lane_and_Road_Attributes&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/BesideTheRoad_Speed&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/TreeCrownDiameter&style&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/SlovakiaBicycleRoutes&style&zip=1
- https://github.com/simon04/coloured-addresses.mapcss/raw/master/dist/coloured-addresses.mapcss
- https://josm.openstreetmap.de/josmfile?page=Styles/Coloured_Streets&style&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Coloured_Suburb&style&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Cycleways&style&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/SlovakiaBicycleRoutes&style&zip=1
- https://github.com/GlassOceanos/indoor-JOSM-style/archive/master.zip
- https://josm.openstreetmap.de/josmfile?page=Styles/PublicTransport&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/PTStops&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/SlovakiaBicycleRoutes&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/SimpleRoofTags&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/SimpleBuildingTags&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/HiDPISupport&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/NumberedCycleNodeNetworks&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/NumberedWalkingNodeNetworks&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/AddressValidator&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/NewHighwayColors&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Noname&zip=1

Validator rules:
+ http://www.openrailwaymap.org/validator/openrailwaymap.validator.mapcss
+ https://josm.openstreetmap.de/josmfile?page=Rules/GermanySpecific&zip=1
+ http://www.openrailwaymap.org/validator/de-openrailwaymap.validator.mapcss
+ https://josm.openstreetmap.de/josmfile?page=Rules/MissingWeekdays&zip=1
+ https://raw.githubusercontent.com/nlehuby/transport_mapcss/master/transport.validator.mapcss

Last errors/warnings:
- W: Not a single layer for the name 'Bing Sat': []
- W: No configuration settings found.  Using hardcoded default values for all pools.
- W: Warning: Failed to scan file 'fr.datagouvfr.jar' for module information. Skipping.

[Stereo]

Screenshot showing lat/lon text (good) and imagery (big pixels)