diff --git a/fluents/workflow.py b/fluents/workflow.py
index e882573..01a302f 100644
--- a/fluents/workflow.py
+++ b/fluents/workflow.py
@@ -1,4 +1,4 @@
-import gtk
+import gtk, gobject
 import sys
 import os
 import inspect
@@ -213,3 +213,167 @@ class WorkflowView (gtk.VBox):
         
         logger.log('debug', 'Function ended: %s' % function.name)
 
+
+class Options(dict):
+    """Options base class.
+    """
+    def __init__(self, *args,**kw):
+        dict.__init__(self, *args, **kw)
+        self['out_plots'] = None
+        self['out_data'] = None
+
+    def _copy_from_list(self, key_list):
+        """Returns suboptions (dictionary) from a list of keys. 
+        """
+        d = {}
+        for key in key_list:
+            d[key] = self.get(key, None)
+        return d
+
+
+class OptionsDialog(gtk.Dialog):
+    """The basic input/output dialog box.
+    
+    This defines the first page of the function options-gui.
+    Any function that invokes a option-gui will inherit from this class.
+    """
+    def __init__(self, data, options, input_names=['X','Y']):
+        gtk.Dialog.__init__(self, 'Input-Output dialog',
+                            None,
+                            gtk.DIALOG_DESTROY_WITH_PARENT,
+                            (gtk.STOCK_OK, gtk.RESPONSE_OK,
+                             gtk.STOCK_CANCEL, gtk.RESPONSE_CANCEL))
+
+        self._options = options
+        self._data = data
+        self._editable = True
+        self.set_size_request(300,400)
+        
+        # create notebook
+        nb = gtk.Notebook()
+
+        # 1. page: input/output
+        #
+        #inputs
+        input_frame = gtk.Frame("Input")
+        hbox = gtk.HBox(True, 8)
+        align = gtk.Alignment(1, 1, 1, 1)
+        align.set_padding(8, 8, 8, 8)
+        align.add(hbox)
+        input_frame.add(align)
+        for i, name in enumerate(input_names):
+            frame = gtk.Frame(name)
+            frame.set_label_align(0.5, 0.5)
+            label = gtk.Label(data[i]._name + "\n" + str(data[i]._array.shape))
+            frame.add(label)
+            hbox.add(frame)
+        
+        #outputs
+        output_frame = gtk.Frame("Output")
+        output_hbox = gtk.HBox(True,4)
+        output_align = gtk.Alignment(1, 1, 1, 1)
+        output_align.set_padding(8, 8, 8, 8) #left padding:8
+        output_align.add(output_hbox)
+        output_frame.add(output_align)
+        
+        # plots
+        plot_list = gtk.ListStore(gobject.TYPE_STRING,
+                                  gobject.TYPE_BOOLEAN)
+        plot_treeview = gtk.TreeView(plot_list)
+
+        # Add plots
+        for plt, name, use in self._options['all_plots']:
+            plot_list.append((name, use))
+            
+        # Renderer for active toggle.
+        active_renderer = gtk.CellRendererToggle()
+        active_renderer.set_property('mode', gtk.CELL_RENDERER_MODE_ACTIVATABLE)
+        active_renderer.connect('toggled', toggled, plot_list)
+        active_column = gtk.TreeViewColumn('Use', active_renderer, active=1)
+
+        # Renderer for plot title.
+        title_renderer = gtk.CellRendererText()
+        title_renderer.set_property('mode', gtk.CELL_RENDERER_MODE_EDITABLE)
+        title_column = gtk.TreeViewColumn('Plot', title_renderer, text=0)
+
+        # Add columns to tree view.
+        plot_treeview.append_column(active_column)
+        plot_treeview.append_column(title_column)
+
+        ## datasets
+        dataset_list = gtk.ListStore(gobject.TYPE_STRING,
+                                     gobject.TYPE_BOOLEAN)
+        dataset_treeview = gtk.TreeView(dataset_list)
+
+        # Add datasets
+        for dat, name, use in self._options['all_data']:
+            dataset_list.append((name, use))
+        
+        # Renderer for active toggle.
+        active_renderer = gtk.CellRendererToggle()
+        active_renderer.set_property('mode', gtk.CELL_RENDERER_MODE_ACTIVATABLE)
+        active_renderer.connect('toggled', toggled, dataset_list)
+        active_column = gtk.TreeViewColumn('Use', active_renderer, active=1)
+
+        # Renderer for plot title.
+        title_renderer = gtk.CellRendererText()
+        title_renderer.set_property('mode', gtk.CELL_RENDERER_MODE_EDITABLE)
+        title_column = gtk.TreeViewColumn('Dataset', title_renderer, text=0)
+
+        # Add columns to tree view.
+        dataset_treeview.append_column(active_column)
+        dataset_treeview.append_column(title_column)
+        
+        # add treeviews to output frame
+        output_hbox.add(plot_treeview)
+        output_hbox.add(dataset_treeview)
+        
+        # vbox for input/spacer/output
+        vbox1 = gtk.VBox()
+        vbox1.add(input_frame)
+        vbox1.add(gtk.HSeparator())
+        vbox1.add(output_frame)
+        
+        # add vbox to notebook
+        nb.append_page(vbox1, gtk.Label("I/O"))
+        self.vbox.add(nb)
+
+        #keep ref to liststores
+        self.dataset_list = dataset_list
+        self.plot_list = plot_list
+
+    def run(self):
+        self.vbox.show_all()
+        return gtk.Dialog.run(self)
+        
+    def set_options(self, options):
+        self._options = options
+        
+    def update_options(self, options):
+        self._options.update(options)
+
+    def set_output(self):
+        # get marked output data
+        out_data = [item[0] for name, mark in self.dataset_list for item in self._options['all_data'] if mark==True and name==item[1]]
+        # get marked plots
+        out_plots = [item[0] for name, mark in self.plot_list for item in self._options['all_plots'] if mark==True and name==item[1]]
+        # update options
+        self._options['out_data'] = out_data
+        self._options['out_plots'] = out_plots
+        
+    def set_editable(self, editable):
+        self._editable = True
+                
+    def set_data(self, data):
+        self._data = data
+
+    def get_data(self):
+        return self._data
+
+    def get_options(self):
+        return self._options
+
+def toggled(renderer, path, store):
+    it = store.get_iter(path)
+    old_value = store.get_value(it, 1)
+    store.set_value(it, 1, not old_value)