magnification lock wanted to disable change of map size due to overly sensitive mouse

[carl@…]

What steps will reproduce the problem?

1. While mapping in JOSM my mouse sometimes misinterprets my hand movements and suddenly increases or decreases map magnification. This is particularly distracting while searching an area for features for a HOT task.
2. I already disabled zooming and other "soft" features in system settings but JOSM still misinterprets some of my movements.

What is the expected result?

I want to be able to set the magnification scale of the map to a certain value (cmd + '+' / cmd + '-' or using the magnification slider) and then lock/unlock magnification changes either with a "lock" icon at the magnification scale or with a shortcut like cmd + '#'.

What happens instead?

While dragging the map with my mouse to search interesting features or even while adding nodes or ways sometimes the map zooms in or out.

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

This happens with a Apple Bluetooth mouse, I'm not sure if other hardware is affected. I have no disabilities that can cause this effect but it feels like a simulation. No other applications show such a behaviour on my system so I think it's not just a bad system setting.

Keep up the good work, JOSM is a great tool!

Revision: 8969
Repository Root: http://josm.openstreetmap.de/svn
Relative URL: ^/trunk
Last Changed Author: Don-vip
Last Changed Date: 2015-10-29 22:15:23 +0100 (Thu, 29 Oct 2015)
Build-Date: 2015-10-30 02:32:24
URL: http://josm.openstreetmap.de/svn/trunk
Repository UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last Changed Rev: 8969

Identification: JOSM/1.5 (8969 de) Mac OS X 10.8.5
Memory Usage: 465 MB / 910 MB (266 MB allocated, but free)
Java version: 1.8.0_60, Oracle Corporation, Java HotSpot(TM) 64-Bit Server VM
VM arguments: [-Djava.library.path=/Users/carl/Downloads/josm-macosx/JOSM.app/Contents/MacOS, -DLibraryDirectory=/Users/carl/Library, -DDocumentsDirectory=/Users/carl/Documents, -DApplicationSupportDirectory=/Users/carl/Library/Application Support, -DCachesDirectory=/Users/carl/Library/Caches, -DSandboxEnabled=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:
- DirectUpload (31694)
- ElevationProfile (31694)
- Mapillary (31694)
- apache-commons (31718)
- apache-http (31687)
- buildings_tools (31694)
- colorscheme (31603)
- editgpx (31603)
- geochat (31694)
- geotools (31603)
- jna (31603)
- jts (31603)
- log4j (31603)
- measurement (31694)
- photo_geotagging (31694)
- reverter (31694)
- routes (31692)
- trafficFlowDirection (13)
- turnrestrictions (31694)
- undelete (31603)
- utilsplugin2 (31694)
- wikipedia (31694)

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