Index: trunk/src/org/openstreetmap/josm/gui/MainFrame.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/MainFrame.java	(revision 17729)
+++ trunk/src/org/openstreetmap/josm/gui/MainFrame.java	(revision 17730)
@@ -6,4 +6,5 @@
 import java.awt.BorderLayout;
 import java.awt.Component;
+import java.awt.ComponentOrientation;
 import java.awt.Image;
 import java.awt.Rectangle;
@@ -15,4 +16,5 @@
 import java.beans.PropertyChangeListener;
 import java.util.List;
+import java.util.Locale;
 import java.util.Objects;
 import java.util.stream.Collectors;
@@ -73,4 +75,13 @@
         this.panel = new MainPanel(MainApplication.getLayerManager());
         setContentPane(new JPanel(new BorderLayout()));
+        setComponentOrientation();
+    }
+
+    private void setComponentOrientation() {
+        ComponentOrientation orientation = ComponentOrientation.getOrientation(Locale.getDefault());
+        if (orientation == ComponentOrientation.RIGHT_TO_LEFT) {
+            Logging.info(tr("Setting component orientation to right-to-left"));
+        }
+        applyComponentOrientation(orientation);
     }