Index: /home/dnaber/workspace/JOSM/src/org/openstreetmap/josm/gui/dialogs/LayerListDialog.java
===================================================================
--- /home/dnaber/workspace/JOSM/src/org/openstreetmap/josm/gui/dialogs/LayerListDialog.java	(revision 592)
+++ /home/dnaber/workspace/JOSM/src/org/openstreetmap/josm/gui/dialogs/LayerListDialog.java	(working copy)
@@ -22,6 +22,7 @@
 import javax.swing.JButton;
 import javax.swing.JLabel;
 import javax.swing.JList;
+import javax.swing.JOptionPane;
 import javax.swing.JPanel;
 import javax.swing.JScrollPane;
 import javax.swing.ListSelectionModel;
@@ -70,6 +71,14 @@
 			Layer l = layer != null ? layer : (Layer)instance.getSelectedValue();
 			if (l instanceof OsmDataLayer && !DontShowAgainInfo.show("delete_layer", tr("Do you really want to delete the whole layer?")))
 				return;
+			if (l instanceof OsmDataLayer && ((OsmDataLayer)l).isModified()) {
+				final int answer = JOptionPane.showConfirmDialog(
+						instance, tr("There are unsaved changes. Delete the layer anwyay?"),
+						tr("Unsaved Changes"), JOptionPane.YES_NO_OPTION);
+				if (answer != JOptionPane.YES_OPTION) {
+					return;
+				}
+			}
 			Main.main.removeLayer(l);
 			if (sel >= instance.getModel().getSize())
 				sel = instance.getModel().getSize()-1;