JOSM invites to upload changeset with no changes

[dieterdreist]

What steps will reproduce the problem?

1. add a tag to a way
2. remove the tag

What is the expected result?

no modifications done, can close without warning

What happens instead?

JOSM urges to uoload

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

this is the changeset with no modifications that was created (besides a new version of the way):
​https://www.openstreetmap.org/changeset/40266105

Maybe this is expected? I should have done "undo" rather than deleting the tag maybe?

URL:http://josm.openstreetmap.de/svn/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2016-06-24 01:49:51 +0200 (Fri, 24 Jun 2016)
Build-Date:2016-06-24 01:34:30
Revision:10473
Relative:URL: ^/trunk

Identification: JOSM/1.5 (10473 en) Mac OS X 10.11.5
Memory Usage: 767 MB / 1820 MB (560 MB allocated, but free)
Java version: 1.8.0_66-b17, Oracle Corporation, Java HotSpot(TM) 64-Bit Server VM
VM arguments: [-Dsun.java2d.opengl=true]
Dataset consistency test: No problems found

Plugins:
- TombPlugin (46)
- alignways (32161)
- apache-commons (32158)
- apache-http (32158)
- buildings_tools (32158)
- ejml (32158)
- geochat (32158)
- geotools (31895)
- imagery_offset_db (32158)
- jts (31906)
- opendata (32289)
- print (32191)
- proj4j (32158)
- reltoolbox (32158)
- reverter (32158)
- undelete (32158)
- utilsplugin2 (32158)

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

Last errors/warnings:
- W: Old style SideButton usage for action org.openstreetmap.josm.gui.history.HistoryBrowserDialog$CloseAction@718c5322
- W: Old style SideButton usage for action org.openstreetmap.josm.gui.help.ContextSensitiveHelpAction@49ebbca9
- W: Old style SideButton usage for action org.openstreetmap.josm.gui.history.HistoryBrowserDialog$ReloadAction@565b6c80
- W: Old style SideButton usage for action org.openstreetmap.josm.gui.history.HistoryBrowserDialog$CloseAction@3c0c2f63
- W: Old style SideButton usage for action org.openstreetmap.josm.gui.help.ContextSensitiveHelpAction@51174121

[stoecker]

Closed as duplicate of #3384.

[stoecker]

In 10481/josm:

Don't use SideButton outside toggle dialogs, see #12994, see #13054