Customizable width and opacity of area outline

[Famlam]

See attached image. At almost all zoom levels where you still have an overview of the general building and town square outline, the actual edge of the building/pedestrian area is partially covered by the ~5mm almost-non-transparant outline of the pedestrian area.

It would be great if either the opacity (transparancy?) of the broad outline, or the width of the outline (now ~5mm) could be customized

Position: ​https://www.openstreetmap.org/#map=19/51.95095/4.55236

URL:https://josm.openstreetmap.de/svn/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2020-09-06 16:54:59 +0200 (Sun, 06 Sep 2020)
Build-Date:2020-09-07 01:30:48
Revision:17013
Relative:URL: ^/trunk

Identification: JOSM/1.5 (17013 nl) Windows 10 64-Bit
OS Build number: Windows 10 Home 2004 (19041)
Memory Usage: 969 MB / 1820 MB (338 MB allocated, but free)
Java version: 1.8.0_261-b12, Oracle Corporation, Java HotSpot(TM) 64-Bit Server VM
Look and Feel: com.sun.java.swing.plaf.windows.WindowsLookAndFeel
Screen: \Display0 1920x1080 (scaling 1.0x1.0)
Maximum Screen Size: 1920x1080
Best cursor sizes: 16x16 -> 32x32, 32x32 -> 32x32
Dataset consistency test: No problems found

Plugins:
+ OpeningHoursEditor (35414)
+ imagery_offset_db (35405)
+ pt_assistant (2.1.10-80-g7d9bba3)
+ tageditor (35258)
+ turnlanes-tagging (283)
+ undelete (35521)
+ utilsplugin2 (35487)

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

Validator rules:
+ %UserProfile%\Documents\tijdelijke bestanden\josm-eigen.validator.mapcss

Last errors/warnings:
- 00043,422 W: java.net.SocketTimeoutException: Read timed out. Oorzaak: java.net.SocketTimeoutException: Read timed out
- 00044,187 W: java.net.SocketTimeoutException: Read timed out. Oorzaak: java.net.SocketTimeoutException: Read timed out