diff --git a/relational_gui/maingui.py b/relational_gui/maingui.py
index 4fec849..412d4c9 100644
--- a/relational_gui/maingui.py
+++ b/relational_gui/maingui.py
@@ -2,8 +2,8 @@
 
 # Form implementation generated from reading ui file 'relational_gui/maingui.ui'
 #
-# Created: Sat Oct 22 15:25:32 2011
-#      by: PyQt4 UI code generator 4.8.3
+# Created: Mon Feb 13 13:21:56 2012
+#      by: PyQt4 UI code generator 4.9.1
 #
 # WARNING! All changes made in this file will be lost!
 
@@ -316,17 +316,29 @@ class Ui_MainWindow(object):
         self.cmdAbout.setText(QtGui.QApplication.translate("MainWindow", "About", None, QtGui.QApplication.UnicodeUTF8))
         self.cmdSurvey.setText(QtGui.QApplication.translate("MainWindow", "Survey", None, QtGui.QApplication.UnicodeUTF8))
         self.groupBox_4.setTitle(QtGui.QApplication.translate("MainWindow", "Operators", None, QtGui.QApplication.UnicodeUTF8))
+        self.cmdProduct.setToolTip(QtGui.QApplication.translate("MainWindow", "Product", None, QtGui.QApplication.UnicodeUTF8))
         self.cmdProduct.setText(QtGui.QApplication.translate("MainWindow", "*", None, QtGui.QApplication.UnicodeUTF8))
+        self.cmdDifference.setToolTip(QtGui.QApplication.translate("MainWindow", "Difference", None, QtGui.QApplication.UnicodeUTF8))
         self.cmdDifference.setText(QtGui.QApplication.translate("MainWindow", "-", None, QtGui.QApplication.UnicodeUTF8))
+        self.cmdUnion.setToolTip(QtGui.QApplication.translate("MainWindow", "Union", None, QtGui.QApplication.UnicodeUTF8))
         self.cmdUnion.setText(QtGui.QApplication.translate("MainWindow", "ᑌ", None, QtGui.QApplication.UnicodeUTF8))
+        self.cmdIntersection.setToolTip(QtGui.QApplication.translate("MainWindow", "Intersection", None, QtGui.QApplication.UnicodeUTF8))
         self.cmdIntersection.setText(QtGui.QApplication.translate("MainWindow", "ᑎ", None, QtGui.QApplication.UnicodeUTF8))
+        self.cmdDivision.setToolTip(QtGui.QApplication.translate("MainWindow", "Division", None, QtGui.QApplication.UnicodeUTF8))
         self.cmdDivision.setText(QtGui.QApplication.translate("MainWindow", "÷", None, QtGui.QApplication.UnicodeUTF8))
+        self.cmdJoin.setToolTip(QtGui.QApplication.translate("MainWindow", "Natural join", None, QtGui.QApplication.UnicodeUTF8))
         self.cmdJoin.setText(QtGui.QApplication.translate("MainWindow", "ᐅᐊ", None, QtGui.QApplication.UnicodeUTF8))
+        self.cmdOuterLeft.setToolTip(QtGui.QApplication.translate("MainWindow", "Left outer join", None, QtGui.QApplication.UnicodeUTF8))
         self.cmdOuterLeft.setText(QtGui.QApplication.translate("MainWindow", "ᐅLEFTᐊ", None, QtGui.QApplication.UnicodeUTF8))
+        self.cmdOuterRight.setToolTip(QtGui.QApplication.translate("MainWindow", "Right outer join", None, QtGui.QApplication.UnicodeUTF8))
         self.cmdOuterRight.setText(QtGui.QApplication.translate("MainWindow", "ᐅRIGHTᐊ", None, QtGui.QApplication.UnicodeUTF8))
+        self.cmdOuter.setToolTip(QtGui.QApplication.translate("MainWindow", "Full outer join", None, QtGui.QApplication.UnicodeUTF8))
         self.cmdOuter.setText(QtGui.QApplication.translate("MainWindow", "ᐅFULLᐊ", None, QtGui.QApplication.UnicodeUTF8))
+        self.cmdProjection.setToolTip(QtGui.QApplication.translate("MainWindow", "Projection", None, QtGui.QApplication.UnicodeUTF8))
         self.cmdProjection.setText(QtGui.QApplication.translate("MainWindow", "π", None, QtGui.QApplication.UnicodeUTF8))
+        self.cmdSelection.setToolTip(QtGui.QApplication.translate("MainWindow", "Selection", None, QtGui.QApplication.UnicodeUTF8))
         self.cmdSelection.setText(QtGui.QApplication.translate("MainWindow", "σ", None, QtGui.QApplication.UnicodeUTF8))
+        self.cmdRename.setToolTip(QtGui.QApplication.translate("MainWindow", "Rename", None, QtGui.QApplication.UnicodeUTF8))
         self.cmdRename.setText(QtGui.QApplication.translate("MainWindow", "ρ", None, QtGui.QApplication.UnicodeUTF8))
         self.cmdArrow.setText(QtGui.QApplication.translate("MainWindow", "➡", None, QtGui.QApplication.UnicodeUTF8))
         self.cmdOptimize.setText(QtGui.QApplication.translate("MainWindow", "Optimize", None, QtGui.QApplication.UnicodeUTF8))
diff --git a/relational_gui/maingui.ui b/relational_gui/maingui.ui
index 684a979..c61d486 100644
--- a/relational_gui/maingui.ui
+++ b/relational_gui/maingui.ui
@@ -54,6 +54,9 @@
           <layout class="QVBoxLayout" name="verticalLayout_10">
            <item>
             <widget class="QPushButton" name="cmdProduct">
+             <property name="toolTip">
+              <string>Product</string>
+             </property>
              <property name="text">
               <string>*</string>
              </property>
@@ -61,6 +64,9 @@
            </item>
            <item>
             <widget class="QPushButton" name="cmdDifference">
+             <property name="toolTip">
+              <string>Difference</string>
+             </property>
              <property name="text">
               <string>-</string>
              </property>
@@ -68,6 +74,9 @@
            </item>
            <item>
             <widget class="QPushButton" name="cmdUnion">
+             <property name="toolTip">
+              <string>Union</string>
+             </property>
              <property name="text">
               <string>ᑌ</string>
              </property>
@@ -75,6 +84,9 @@
            </item>
            <item>
             <widget class="QPushButton" name="cmdIntersection">
+             <property name="toolTip">
+              <string>Intersection</string>
+             </property>
              <property name="text">
               <string>ᑎ</string>
              </property>
@@ -82,6 +94,9 @@
            </item>
            <item>
             <widget class="QPushButton" name="cmdDivision">
+             <property name="toolTip">
+              <string>Division</string>
+             </property>
              <property name="text">
               <string>÷</string>
              </property>
@@ -89,6 +104,9 @@
            </item>
            <item>
             <widget class="QPushButton" name="cmdJoin">
+             <property name="toolTip">
+              <string>Natural join</string>
+             </property>
              <property name="text">
               <string>ᐅᐊ</string>
              </property>
@@ -96,6 +114,9 @@
            </item>
            <item>
             <widget class="QPushButton" name="cmdOuterLeft">
+             <property name="toolTip">
+              <string>Left outer join</string>
+             </property>
              <property name="text">
               <string>ᐅLEFTᐊ</string>
              </property>
@@ -103,6 +124,9 @@
            </item>
            <item>
             <widget class="QPushButton" name="cmdOuterRight">
+             <property name="toolTip">
+              <string>Right outer join</string>
+             </property>
              <property name="text">
               <string>ᐅRIGHTᐊ</string>
              </property>
@@ -110,6 +134,9 @@
            </item>
            <item>
             <widget class="QPushButton" name="cmdOuter">
+             <property name="toolTip">
+              <string>Full outer join</string>
+             </property>
              <property name="text">
               <string>ᐅFULLᐊ</string>
              </property>
@@ -117,6 +144,9 @@
            </item>
            <item>
             <widget class="QPushButton" name="cmdProjection">
+             <property name="toolTip">
+              <string>Projection</string>
+             </property>
              <property name="text">
               <string>π</string>
              </property>
@@ -124,6 +154,9 @@
            </item>
            <item>
             <widget class="QPushButton" name="cmdSelection">
+             <property name="toolTip">
+              <string>Selection</string>
+             </property>
              <property name="text">
               <string>σ</string>
              </property>
@@ -131,6 +164,9 @@
            </item>
            <item>
             <widget class="QPushButton" name="cmdRename">
+             <property name="toolTip">
+              <string>Rename</string>
+             </property>
              <property name="text">
               <string>ρ</string>
              </property>