diff --git a/array2xls/gui.py b/array2xls/gui.py
index a0397fb..7b19db1 100644
--- a/array2xls/gui.py
+++ b/array2xls/gui.py
@@ -54,7 +54,6 @@ class FieldPanel(tk.Frame):
         self.rbtn_combine.pack(anchor=tk.W)
         self.listbox = tk.Listbox(self, selectmode=tk.MULTIPLE, activestyle='none')
         self.listbox.pack(fill=tk.X, ipady=5, ipadx=5)
-        self.listbox.insert(0, "HELLO")
         self.pack(side=tk.TOP, fill=tk.X)
 
     def disable_radio_btn(self):
@@ -80,6 +79,18 @@ class FieldPanel(tk.Frame):
         self.enable_listbox()
         self.enable_radio_btn()
 
+    def set_listbox_content(self, choices, selection):
+        self.enable_listbox()
+        current = self.listbox.size()
+        self.listbox.selection_clear(0, current)
+        self.listbox.delete(0,current)
+        for i, element in enumerate(choices):
+            self.listbox.insert(tk.END, element)
+            if element in selection:
+                self.listbox.selection_set(i)
+        self.disable_listbox()
+
+
 
 class ActionPanel(tk.Frame):
 
@@ -122,7 +133,7 @@ class Application(tk.Frame):
         self.reset()
         self.file_panel.clear_text()
         opts = {
-            'initialdir': '~',
+            'initialdir': '~/_signalyse test',
             'filetypes': [('Signalyse Statistics', '.stx'), ('Signalyse Data', '.dat'), ('Sensovation Data', '.csv')],
             'multiple': True}
         file_selection = tk.filedialog.askopenfilename(**opts)
@@ -138,6 +149,7 @@ class Application(tk.Frame):
             self.reset()
             return
         self.field_panel.enable_radio_btn()
+        self.field_panel.set_listbox_content(self.file_validator.data_fields, self.file_validator.defaults)
 
 
 
diff --git a/array2xls/validators.py b/array2xls/validators.py
index 73da97f..807046a 100644
--- a/array2xls/validators.py
+++ b/array2xls/validators.py
@@ -5,52 +5,87 @@ from collections import namedtuple
 class ValidationError(ValueError):
     pass
 
-Validator = namedtuple('Validator', 'type validate extension')
+Validator = namedtuple('Validator', 'type extension validate id_fields data_fields defaults')
 DataFile = namedtuple('DataFile', 'path separator')
 
 def validate_stx(lines):
     iterator = iter(lines)
     line = next(iterator)
-    if not line.startswith('Report_Format\t2'):
+    if not line.startswith('Report_Format:\t2'):
         raise ValidationError('1 Unsupported File;' + line)
     for line in iterator:
         if line.startswith('Probe_Name\t'):
             break
     else:
         raise ValidationError('1 Unsupported File')
-    for line in iterator:
-        probe_name, rest = line.split('\t', 1)
-        separator = ',' if rest.count(',') > rest.count('.') else '.'
-        return separator
-    else:
+    try:
+        line = next(iterator)
+        _, numeric_data = line.split('\t', 1)
+    except (ValueError, StopIteration):
         raise ValidationError('No Data Present')
+    separator = ',' if numeric_data.count(',') > numeric_data.count('.') else '.'
+    return separator
 
 
 def validate_dat(lines):
     iterator = iter(lines)
-    if not next(iterator).startswith('Report_Format\t2'):
+    if not next(iterator).startswith('Report_Format:\t2'):
         raise ValidationError('Unsupported File')
     for line in iterator:
         if line.startswith('Dot_Number\t'):
             break
     else:
         raise ValidationError('Unsupported File')
-    for line in iterator:
-        probe_name, rest = line.split('\t', 3)
-        separator = ',' if rest.count(',') > rest.count('.') else '.'
-        return separator
-    else:
+    try:
+        line = next(iterator)
+        _, _, _, numeric_data = line.split('\t', 3)
+    except (ValueError, StopIteration):
         raise ValidationError('No Data Present')
+    separator = ',' if numeric_data.count(',') > numeric_data.count('.') else '.'
+    return separator
+
 
 def validate_csv(lines):
-    pass
+    iterator = iter(lines)
+    if not next(iterator).startswith(' ID '):
+        raise ValidationError('Unsupported File')
+    try:
+        line = next(iterator)
+        _, numeric_data = line.split('\t', 1)
+    except (ValueError, StopIteration):
+        raise ValidationError('No Data Present')
+    separator = ',' if numeric_data.count(',') > numeric_data.count('.') else '.'
+    return separator
+
+
+stx_validator = Validator(
+    'Signalyse Statistic Files', '.stx', validate_stx,
+    ['Probe_Name'],
+    ['Count', 'Net_Signal', 'Net_Signal_SD', 'Net_Integral', 'Net_Integral_SD', 'Proc_Control'],
+    ['Net_Signal', 'Net_Signal_SD', 'Net_Integral', 'Net_Integral_SD'])
+
+dat_validator = Validator(
+    'Signalyse Data Files', '.dat', validate_dat,
+    ['Dot_Number', 'Probe_Name', 'Gene_Name', 'Col', 'Row'],
+    ['X[Pix]', 'Y[Pix]', 'DX[Pix]', 'DY[Pix]', 'Spot_Diameter', 'ROI_Width', 'ROI_Heigth', 'Pixels', 'Bkg',
+     'Bkg_SD', 'Net_Signal', 'Net_Signal_SD', 'Net_Integral', 'Net_Integral_SD', 'Acc_Number', 'Proc_Control'],
+    ['Bkg', 'Bkg_SD', 'Net_Signal', 'Net_Signal_SD', 'Net_Integral', 'Net_Integral_SD'] )
+
+csv_validator = Validator(
+    'Sensovation Data Files', '.csv', validate_csv,
+    [' ID '],
+    ['Pos.X', 'Pos.Y', 'Bkg.Mean', 'Spot.Mean', 'Bkg.Median', 'Spot.Median', 'Bkg.StdDev', 'Spot.StdDev',
+     'Bkg.Sum', 'Spot.Sum', 'Bkg.Area', 'Spot.Area', 'Spot.Sat. (%)', 'Found', 'Pos.Nom.X', 'Pos.Nom.Y', 'Dia.',
+     'Rect.', 'Contour'],
+    ['Bkg.Mean', 'Spot.Mean', 'Bkg.Median', 'Spot.Median', 'Bkg.StdDev', 'Spot.StdDev', 'Bkg.Sum', 'Spot.Sum'] )
 
 validation_map = {
-    '.stx': Validator('Signalyse Statistic Files', validate_stx, '.stx'),
-    '.dat': Validator('Signalyse Data Files', validate_dat, '.dat'),
-    '.csv': Validator('Sensovation Data Files', validate_csv, '.csv')
+    stx_validator.extension: stx_validator,
+    dat_validator.extension: dat_validator,
+    csv_validator.extension: csv_validator
 }
 
+
 def guess_validator(unvalidated):
     # get the validation method by examining the first file
     _, extension = os.path.splitext(unvalidated[0])