Index: /trunk/src/org/openstreetmap/josm/gui/dialogs/properties/PropertiesDialog.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/gui/dialogs/properties/PropertiesDialog.java	(revision 14475)
+++ /trunk/src/org/openstreetmap/josm/gui/dialogs/properties/PropertiesDialog.java	(revision 14476)
@@ -96,4 +96,5 @@
 import org.openstreetmap.josm.gui.tagging.presets.TaggingPresetType;
 import org.openstreetmap.josm.gui.util.HighlightHelper;
+import org.openstreetmap.josm.gui.util.TableHelper;
 import org.openstreetmap.josm.gui.widgets.CompileSearchTextDecorator;
 import org.openstreetmap.josm.gui.widgets.DisableShortcutsOnFocusGainedTextField;
@@ -309,4 +310,5 @@
         tagData.setColumnIdentifiers(new String[]{tr("Key"), tr("Value")});
         tagTable.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
+        tagTable.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
         tagTable.getTableHeader().setReorderingAllowed(false);
 
@@ -333,4 +335,5 @@
         membershipData.setColumnIdentifiers(new String[]{tr("Member Of"), tr("Role"), tr("Position")});
         membershipTable.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
+        membershipTable.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
 
         TableColumnModel mod = membershipTable.getColumnModel();
@@ -670,4 +673,8 @@
         pluginHook.setVisible(hasSelection);
 
+        // resize tables to fit content
+        TableHelper.computeColumnsWidth(tagTable);
+        TableHelper.computeColumnsWidth(membershipTable);
+
         int selectedIndex;
         if (selectedTag != null && (selectedIndex = findViewRow(tagTable, tagData, selectedTag)) != -1) {
Index: /trunk/src/org/openstreetmap/josm/gui/util/TableHelper.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/gui/util/TableHelper.java	(revision 14475)
+++ /trunk/src/org/openstreetmap/josm/gui/util/TableHelper.java	(revision 14476)
@@ -17,5 +17,4 @@
 
     /**
-     * (originally from @class org.openstreetmap.josm.gui.preferences.SourceEditor)
      * adjust the preferred width of column col to the maximum preferred width of the cells
      * requires JTable.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
@@ -34,3 +33,15 @@
         tbl.getColumnModel().getColumn(col).setPreferredWidth(Math.min(maxwidth+10, maxColumnWidth));
     }
+
+    /**
+     * adjust the table's columns to fit their content best
+     * requires JTable.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
+     * @param tbl table
+     * @since 14476
+     */
+    public static void computeColumnsWidth(JTable tbl) {
+        for (int column = 0; column < tbl.getColumnCount(); column++) {
+            adjustColumnWidth(tbl, column, Integer.MAX_VALUE);
+        }
+    }
 }