Index: trunk/src/org/openstreetmap/josm/gui/dialogs/changeset/ChangesetCacheTableCellRenderer.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/dialogs/changeset/ChangesetCacheTableCellRenderer.java	(revision 7706)
+++ trunk/src/org/openstreetmap/josm/gui/dialogs/changeset/ChangesetCacheTableCellRenderer.java	(revision 7712)
@@ -36,5 +36,5 @@
         setForeground(UIManager.getColor("Table.foreground"));
         setFont(UIManager.getFont("Table.font"));
-        setToolTipText("");
+        setToolTipText(null);
     }
 
@@ -51,5 +51,5 @@
     protected void renderId(Changeset cs) {
         setText(Integer.toString(cs.getId()));
-        setToolTipText("");
+        setToolTipText(null);
     }
 
@@ -72,5 +72,5 @@
             setText(trc("changeset.state", "Closed"));
         }
-        setToolTipText("");
+        setToolTipText(null);
     }
 
@@ -93,10 +93,10 @@
             setText(DateUtils.formatDateTime(d, DateFormat.SHORT, DateFormat.SHORT));
         }
-        setToolTipText("");
+        setToolTipText(null);
     }
 
     protected void renderDiscussions(Changeset cs) {
         setText(Integer.toString(cs.getCommentsCount()));
-        setToolTipText("");
+        setToolTipText(null);
     }
 
Index: trunk/src/org/openstreetmap/josm/gui/dialogs/changeset/ChangesetContentTableCellRenderer.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/dialogs/changeset/ChangesetContentTableCellRenderer.java	(revision 7706)
+++ trunk/src/org/openstreetmap/josm/gui/dialogs/changeset/ChangesetContentTableCellRenderer.java	(revision 7712)
@@ -43,5 +43,5 @@
     protected void renderId(HistoryOsmPrimitive primitive) {
         setText(Long.toString(primitive.getId()));
-        setToolTipText("");
+        setToolTipText(null);
     }
 
@@ -52,5 +52,5 @@
         case DELETED: setText(tr("Deleted")); break;
         }
-        setToolTipText("");
+        setToolTipText(null);
     }
 
Index: trunk/src/org/openstreetmap/josm/gui/dialogs/changeset/query/UrlBasedQueryPanel.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/dialogs/changeset/query/UrlBasedQueryPanel.java	(revision 7706)
+++ trunk/src/org/openstreetmap/josm/gui/dialogs/changeset/query/UrlBasedQueryPanel.java	(revision 7712)
@@ -172,5 +172,5 @@
             if ("valid".equals(getCurrentFeedback())) return;
             lblValid.setIcon(ImageProvider.get("dialogs", "valid"));
-            lblValid.setToolTipText("");
+            lblValid.setToolTipText(null);
             lblValid.putClientProperty("valid", "valid");
         }
Index: trunk/src/org/openstreetmap/josm/gui/download/BoundingBoxSelection.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/download/BoundingBoxSelection.java	(revision 7706)
+++ trunk/src/org/openstreetmap/josm/gui/download/BoundingBoxSelection.java	(revision 7712)
@@ -184,5 +184,5 @@
     protected void resetErrorMessage(JosmTextField tf) {
         tf.setBorder(UIManager.getBorder("TextField.border"));
-        tf.setToolTipText("");
+        tf.setToolTipText(null);
     }
 
Index: trunk/src/org/openstreetmap/josm/gui/io/UploadStrategySelectionPanel.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/io/UploadStrategySelectionPanel.java	(revision 7706)
+++ trunk/src/org/openstreetmap/josm/gui/io/UploadStrategySelectionPanel.java	(revision 7712)
@@ -342,5 +342,5 @@
             JMultilineLabel lbl = lblStrategies.get(UploadStrategy.SINGLE_REQUEST_STRATEGY);
             lbl.setText(tr("Upload data in one request"));
-            lbl.setToolTipText("");
+            lbl.setToolTipText(null);
             lblNumRequests.get(UploadStrategy.SINGLE_REQUEST_STRATEGY).setVisible(true);