Index: /trunk/src/org/openstreetmap/josm/actions/mapmode/DrawAction.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/actions/mapmode/DrawAction.java	(revision 13224)
+++ /trunk/src/org/openstreetmap/josm/actions/mapmode/DrawAction.java	(revision 13225)
@@ -30,4 +30,5 @@
 import javax.swing.JMenuItem;
 import javax.swing.JOptionPane;
+import javax.swing.SwingUtilities;
 
 import org.openstreetmap.josm.Main;
@@ -348,6 +349,9 @@
         if (!MainApplication.getMap().mapView.isActiveLayerDrawable())
             return;
-        computeHelperLine();
-        addHighlighting();
+        // Make sure helper line is computed later (causes deadlock in selection event chain otherwise)
+        SwingUtilities.invokeLater(() -> {
+            computeHelperLine();
+            addHighlighting();
+        });
     }