diff --git a/apps/modes_gui b/apps/modes_gui
index f2678e8..ee9cf52 100755
--- a/apps/modes_gui
+++ b/apps/modes_gui
@@ -90,16 +90,23 @@ class mainwindow(QtGui.QMainWindow):
 
         #hook up the update signal
         self.ui.list_aircraft.selectionModel().currentRowChanged.connect(self.dashboard_mapper.setCurrentModelIndex)
-        #self.ui.list_aircraft.selectionModel().currentRowChanged.connect(self.update_heading_widget)
+        self.ui.list_aircraft.selectionModel().currentRowChanged.connect(self.update_heading_widget)
+        self.datamodel.dataChanged.connect(self.update_heading_widget_data)
         self.ui.list_aircraft.selectionModel().currentRowChanged.connect(self.update_rssi_widget)
 
     def update_heading_widget(self, index):
-        heading = index.model().data(index.model().index(index.row(), 7)).toDouble()[0]
-        self.ui.compass_heading.setValue(heading)
+        if index.model() is not None:
+            heading = index.model().data(index.model().index(index.row(), 7)).toDouble()[0]
+            self.ui.compass_heading.setValue(heading)
+
+    def update_heading_widget_data(self, startIndex, endIndex):
+        index = self.ui.list_aircraft.selectionModel().currentIndex()
+        self.update_heading_widget(index)
 
     def update_rssi_widget(self, index):
-        rssi = index.model().data(index.model().index(index.row(), 2)).toDouble()[0]
-        self.ui.prog_rssi.setValue(rssi)
+        if index.model() is not None:
+            rssi = index.model().data(index.model().index(index.row(), 2)).toDouble()[0]
+            self.ui.prog_rssi.setValue(rssi)
 
     #goes and gets valid antenna, sample rate options from the device and grays out appropriate things
     def populate_source_options(self):
@@ -242,11 +249,12 @@ class mainwindow(QtGui.QMainWindow):
 #and display ident if available, ICAO otherwise
 class ICAOViewDelegate(QtGui.QStyledItemDelegate):
     def paint(self, painter, option, index):
+        #draw selection rectangle
         if option.state & QtGui.QStyle.State_Selected:
             painter.setBrush(QtGui.QPalette().highlight())
-            #painter.setBrush(QtGui.QBrush(QtCore.Qt.red))
             painter.drawRect(option.rect)
-        
+
+        #if there's an ident available, use it. otherwise print the ICAO
         if index.model().data(index.model().index(index.row(), 9)) != QtCore.QVariant():
             paintstr = index.model().data(index.model().index(index.row(), 9)).toString()
         else:
@@ -258,9 +266,7 @@ class ICAOViewDelegate(QtGui.QStyledItemDelegate):
         age = min(age, max_age)
         alpha = int(0xFF - (0xBF / max_age) * age)
         painter.setPen(QtGui.QColor(0, 0, 0, alpha))
-        #QtGui.QStyledItemDelegate.paint(self, painter, option, index)
         painter.drawText(option.rect.left()+3, option.rect.top(), option.rect.width(), option.rect.height(), option.displayAlignment, paintstr)
-        #TODO: draw highlight for selection
 
 #the data model used to display dashboard data.
 class dashboard_data_model(QtCore.QAbstractTableModel):
@@ -289,6 +295,10 @@ class dashboard_data_model(QtCore.QAbstractTableModel):
         if self._data[index.row()][index.column()] is None:
             return QtCore.QVariant()
         else:
+            #if there's a dedicated precision for that column, print it out with the specified precision.
+            #this only works well if you DON'T have other views/widgets that depend on numeric data coming out.
+            #i don't like this, but it works for now. unfortunately it seems like Qt doesn't give you a
+            #good alternative.
             if self._precisions[index.column()] is not None:
                 return QtCore.QVariant("%.*f" % (self._precisions[index.column()], self._data[index.row()][index.column()]))
             else:
@@ -311,11 +321,7 @@ class dashboard_data_model(QtCore.QAbstractTableModel):
         self.lock.release()
 
     #addRecord implements an upsert on self._data; that is,
-    #it updates the row if the ICAO exists, or else it creates a new
-    #row with the appropriate information. in any case, it maintains sorting
-    #by ICAO, emits beginInsertRows() and endInsertRows()
-    #NOTE: could also use QSortFilterProxyModel to handle sorting without
-    #having to do it in the model, but this isn't exactly hard
+    #it updates the row if the ICAO exists, or else it creates a new row.
     def addRecord(self, record):
         self.lock.acquire()
         icaos = [x[0] for x in self._data]