diff --git a/src/sextante/ftools/Clip.py b/src/sextante/ftools/Clip.py
index 14b0569e782..86915060a61 100644
--- a/src/sextante/ftools/Clip.py
+++ b/src/sextante/ftools/Clip.py
@@ -6,7 +6,6 @@ from PyQt4.QtGui import *
 from qgis.core import *
 from sextante.parameters.ParameterVector import ParameterVector
 from sextante.core.QGisLayers import QGisLayers
-from sextante.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
 from sextante.outputs.OutputVector import OutputVector
 from sextante.ftools import ftools_utils
 from sextante.core.SextanteLog import SextanteLog
@@ -33,10 +32,10 @@ class Clip(GeoAlgorithm):
         vlayerB = QGisLayers.getObjectFromUri(self.getParameterValue(Clip.INPUT2))
         GEOS_EXCEPT = True
         FEATURE_EXCEPT = True
-        vproviderA = self.vlayerA.dataProvider()
+        vproviderA = vlayerA.dataProvider()
         allAttrsA = vproviderA.attributeIndexes()
         vproviderA.select( allAttrsA )
-        vproviderB = self.vlayerB.dataProvider()
+        vproviderB = vlayerB.dataProvider()
         allAttrsB = vproviderB.attributeIndexes()
         vproviderB.select( allAttrsB )
         # check for crs compatibility
@@ -59,10 +58,10 @@ class Clip(GeoAlgorithm):
         # there is selection in input layer
         if useSelection:
           nFeat = vlayerA.selectedFeatureCount()
-          selectionA = self.vlayerA.selectedFeatures()
+          selectionA = vlayerA.selectedFeatures()
           # we have selection in overlay layer
           if useSelection2:
-            selectionB = self.vlayerB.selectedFeaturesIds()
+            selectionB = vlayerB.selectedFeaturesIds()
             for inFeatA in selectionA:
               nElement += 1
               progress.setPercentage(int(nElement/nFeat * 100))
@@ -156,7 +155,7 @@ class Clip(GeoAlgorithm):
           nFeat = vproviderA.featureCount()
           # we have selection in overlay layer
           if useSelection2:
-            selectionB = self.vlayerB.selectedFeaturesIds()
+            selectionB = vlayerB.selectedFeaturesIds()
             while vproviderA.nextFeature( inFeatA ):
               nElement += 1
               progress.setPercentage(int(nElement/nFeat * 100))
diff --git a/src/sextante/gui/ParametersPanel.py b/src/sextante/gui/ParametersPanel.py
index bc3ad01495e..849f40713cd 100644
--- a/src/sextante/gui/ParametersPanel.py
+++ b/src/sextante/gui/ParametersPanel.py
@@ -1,4 +1,5 @@
 import os
+import locale
 from PyQt4 import QtCore, QtGui
 from sextante.gui.OutputSelectionPanel import OutputSelectionPanel
 from sextante.core.QGisLayers import QGisLayers
@@ -219,9 +220,7 @@ class ParametersPanel(QtGui.QWidget):
             else:
                 layers = QGisLayers.getTables()
             if len(layers)>0:
-                fields = self.getFields(layers[0])
-                for i in fields:
-                    item.addItem(fields[i].name())
+                item.addItems(self.getFields(layers[0], param.datatype))
         elif isinstance(param, ParameterSelection):
             item = QtGui.QComboBox()
             item.addItems(param.options)
@@ -266,12 +265,26 @@ class ParametersPanel(QtGui.QWidget):
         for child in children:
             widget = self.valueItems[child]
             widget.clear()
-            fields = self.getFields(layer)
-            for i in fields:
-                widget.addItem(fields[i].name())
+            widget.addItems(self.getFields(layer, self.alg.getParameterFromName(child).datatype))
 
-    def getFields(self, layer):
-        return layer.dataProvider().fields()
+    def getFields(self, layer, datatype):
+        fieldTypes = []
+        if datatype == ParameterTableField.DATA_TYPE_STRING:
+            fieldTypes = [QVariant.String]
+        elif datatype == ParameterTableField.DATA_TYPE_NUMBER:
+            fieldTypes = [QVariant.Int, QVariant.Double]
+
+        fieldNames = []
+        fieldMap = layer.pendingFields()
+        if len(fieldTypes) == 0:
+            for idx, field in fieldMap.iteritems():
+                if not field.name() in fieldNames:
+                    fieldNames.append( unicode( field.name() ) )
+        else:
+            for idx, field in fieldMap.iteritems():
+                if field.type() in fieldTypes and not field.name() in fieldNames:
+                    fieldNames.append( unicode( field.name() ) )
+        return sorted( fieldNames, cmp=locale.strcoll )
 
     def somethingDependsOnThisParameter(self, parent):
         for param in self.alg.parameters:
diff --git a/src/sextante/parameters/ParameterTableField.py b/src/sextante/parameters/ParameterTableField.py
index e1294332f76..cc77e25549d 100644
--- a/src/sextante/parameters/ParameterTableField.py
+++ b/src/sextante/parameters/ParameterTableField.py
@@ -2,10 +2,15 @@ from sextante.parameters.Parameter import Parameter
 
 class ParameterTableField(Parameter):
 
-    def __init__(self, name="", description="", parent=None):
+    DATA_TYPE_NUMBER = 0
+    DATA_TYPE_STRING = 1
+    DATA_TYPE_ANY = -1
+
+    def __init__(self, name="", description="", parent=None, datatype=-1):
         Parameter.__init__(self, name, description)
         self.parent = parent
         self.value = None
+        self.datatype = datatype
 
     def getValueAsCommandLineParameter(self):
         return "\"" + str(self.value) + "\""
@@ -15,11 +20,15 @@ class ParameterTableField(Parameter):
 
     def serialize(self):
         return self.__module__.split(".")[-1] + "|" + self.name + "|" + self.description +\
-                        "|" + str(self.parent)
+                "|" + str(self.parent) + "|" + str(self.datatype)
+
 
     def deserialize(self, s):
         tokens = s.split("|")
-        return ParameterTableField(tokens[0], tokens[1], tokens[2])
+        if len(tokens) == 4:
+            return ParameterTableField(tokens[0], tokens[1], tokens[2], int(tokens[3]))
+        else:
+            return ParameterTableField(tokens[0], tokens[1], tokens[2])
 
     def __str__(self):
         return self.name + " <" + self.__module__.split(".")[-1] +" from " + self.value + ">"