Index: trunk/src/org/openstreetmap/josm/gui/io/BasicUploadSettingsPanel.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/io/BasicUploadSettingsPanel.java	(revision 17473)
+++ trunk/src/org/openstreetmap/josm/gui/io/BasicUploadSettingsPanel.java	(revision 17475)
@@ -164,4 +164,5 @@
     protected void automaticallyAddSource() {
         final String source = MainApplication.getMap().mapView.getLayerInformationForSourceTag();
+        hcbUploadSource.getModel().setSelectedItem(null); // fix #20134
         hcbUploadSource.setText(Utils.shortenString(source, Changeset.MAX_CHANGESET_TAG_LENGTH));
         changesetSourceModel.setComment(hcbUploadSource.getText()); // Fix #9965