diff --git a/app.py b/app.py
index a2b76f9..cd4c055 100755
--- a/app.py
+++ b/app.py
@@ -198,7 +198,8 @@ class SplashScreen(wx.SplashScreen):
         self.control = Controller(self.main)
         
         self.fc = wx.FutureCall(1, self.ShowMain)
-        wx.FutureCall(1, parse_comand_line)
+        options, args = parse_comand_line()
+        wx.FutureCall(1, use_cmd_optargs, options, args)
 
         # Check for updates
         from threading import Thread
@@ -224,6 +225,24 @@ class SplashScreen(wx.SplashScreen):
         if self.fc.IsRunning():
             self.Raise()
 
+
+def non_gui_startup(options, args):
+    lang = 'en'
+    _ = i18n.InstallLanguage(lang)
+
+    from invesalius.control import Controller
+    from invesalius.project import Project
+
+    session = ses.Session()
+    if not session.ReadSession():
+        session.CreateItens()
+        session.SetLanguage(lang)
+        session.WriteSessionFile()
+
+    control = Controller(None)
+
+    use_cmd_optargs(options, args)
+
 # ------------------------------------------------------------------
 
 
@@ -241,6 +260,10 @@ def parse_comand_line():
                       action="store_true",
                       dest="debug")
 
+    parser.add_option('--no-gui',
+                      action='store_true',
+                      dest='no_gui')
+
     # -i or --import: import DICOM directory
     # chooses largest series
     parser.add_option("-i", "--import",
@@ -254,7 +277,10 @@ def parse_comand_line():
                       help="To open a project and export it to STL for all mask presets.")
 
     options, args = parser.parse_args()
+    return options, args
+
 
+def use_cmd_optargs(options, args):
     # If debug argument...
     if options.debug:
         Publisher.subscribe(print_events, Publisher.ALL_TOPICS)
@@ -333,8 +359,13 @@ def main():
     """
     Initialize InVesalius GUI
     """
-    application = InVesalius(0)
-    application.MainLoop()
+    options, args = parse_comand_line()
+
+    if options.no_gui:
+        non_gui_startup(options, args)
+    else:
+        application = InVesalius(0)
+        application.MainLoop()
 
 if __name__ == '__main__':
     #Is needed because of pyinstaller
diff --git a/invesalius/constants.py b/invesalius/constants.py
index 8664b7d..450468f 100644
--- a/invesalius/constants.py
+++ b/invesalius/constants.py
@@ -686,19 +686,19 @@ BTNS_IMG_MKS = {IR1: {0: 'LEI'},
             IR2: {1: 'REI'},
             IR3: {2: 'NAI'}}
 
-TIPS_IMG = [wx.ToolTip(_("Select left ear in image")),
-            wx.ToolTip(_("Select right ear in image")),
-            wx.ToolTip(_("Select nasion in image"))]
+TIPS_IMG = [_("Select left ear in image"),
+            _("Select right ear in image"),
+            _("Select nasion in image")]
 
 BTNS_TRK = {TR1: {3: _('LET')},
             TR2: {4: _('RET')},
             TR3: {5: _('NAT')},
             SET: {6: _('SET')}}
 
-TIPS_TRK = [wx.ToolTip(_("Select left ear with spatial tracker")),
-            wx.ToolTip(_("Select right ear with spatial tracker")),
-            wx.ToolTip(_("Select nasion with spatial tracker")),
-            wx.ToolTip(_("Show set coordinates in image"))]
+TIPS_TRK = [_("Select left ear with spatial tracker"),
+            _("Select right ear with spatial tracker"),
+            _("Select nasion with spatial tracker"),
+            _("Show set coordinates in image")]
 
 CAL_DIR = os.path.abspath(os.path.join(FILE_PATH, '..', 'navigation', 'mtc_files', 'CalibrationFiles'))
 MAR_DIR = os.path.abspath(os.path.join(FILE_PATH, '..', 'navigation', 'mtc_files', 'Markers'))
diff --git a/invesalius/data/slice_.py b/invesalius/data/slice_.py
index 48f6f46..d23eb81 100644
--- a/invesalius/data/slice_.py
+++ b/invesalius/data/slice_.py
@@ -353,19 +353,22 @@ class Slice(object):
 
         # TODO: merge this code with apply_slice_buffer_to_mask
         b_mask = self.buffer_slices["AXIAL"].mask
-        n = self.buffer_slices["AXIAL"].index + 1
-        self.current_mask.matrix[n, 1:, 1:] = b_mask
-        self.current_mask.matrix[n, 0, 0] = 1
+        if b_mask:
+            n = self.buffer_slices["AXIAL"].index + 1
+            self.current_mask.matrix[n, 1:, 1:] = b_mask
+            self.current_mask.matrix[n, 0, 0] = 1
 
         b_mask = self.buffer_slices["CORONAL"].mask
-        n = self.buffer_slices["CORONAL"].index + 1
-        self.current_mask.matrix[1:, n, 1:] = b_mask
-        self.current_mask.matrix[0, n, 0] = 1
+        if b_mask:
+            n = self.buffer_slices["CORONAL"].index + 1
+            self.current_mask.matrix[1:, n, 1:] = b_mask
+            self.current_mask.matrix[0, n, 0] = 1
 
         b_mask = self.buffer_slices["SAGITAL"].mask
-        n = self.buffer_slices["SAGITAL"].index + 1
-        self.current_mask.matrix[1:, 1:, n] = b_mask
-        self.current_mask.matrix[0, 0, n] = 1
+        if b_mask:
+            n = self.buffer_slices["SAGITAL"].index + 1
+            self.current_mask.matrix[1:, 1:, n] = b_mask
+            self.current_mask.matrix[0, 0, n] = 1
 
         if to_reload:
             Publisher.sendMessage('Reload actual slice')
@@ -882,8 +885,8 @@ class Slice(object):
                     self.current_mask.matrix[n+1, 1:, 1:] = m
             else:
                 slice_ = self.buffer_slices[orientation].image
-                print ">>>", slice_, index
-                self.buffer_slices[orientation].mask = (255 * ((slice_ >= thresh_min) & (slice_ <= thresh_max))).astype('uint8')
+                if slice_:
+                    self.buffer_slices[orientation].mask = (255 * ((slice_ >= thresh_min) & (slice_ <= thresh_max))).astype('uint8')
 
             # Update viewer
             #Publisher.sendMessage('Update slice viewer')
diff --git a/invesalius/data/vtk_utils.py b/invesalius/data/vtk_utils.py
index c24e224..84b1bd9 100644
--- a/invesalius/data/vtk_utils.py
+++ b/invesalius/data/vtk_utils.py
@@ -44,7 +44,10 @@ def ShowProgress(number_of_filters = 1,
     progress = [0]
     last_obj_progress = [0]
     if (dialog_type == "ProgressDialog"):
-        dlg = ProgressDialog(100)
+        try:
+            dlg = ProgressDialog(100)
+        except wx._core.PyNoAppError:
+            return lambda obj, label: 0
 
 
     # when the pipeline is larger than 1, we have to consider this object
diff --git a/invesalius/gui/task_navigator.py b/invesalius/gui/task_navigator.py
index cec335f..ebfd9b8 100644
--- a/invesalius/gui/task_navigator.py
+++ b/invesalius/gui/task_navigator.py
@@ -247,7 +247,7 @@ class NeuronavigationPanel(wx.Panel):
             n = btns_img[k].keys()[0]
             lab = btns_img[k].values()[0]
             self.btns_coord[n] = wx.ToggleButton(self, k, label=lab, size=wx.Size(45, 23))
-            self.btns_coord[n].SetToolTip(tips_img[n])
+            self.btns_coord[n].SetToolTip(wx.ToolTip(tips_img[n]))
             self.btns_coord[n].Bind(wx.EVT_TOGGLEBUTTON, self.OnImageFiducials)
 
         # Push buttons for tracker fiducials
@@ -258,7 +258,7 @@ class NeuronavigationPanel(wx.Panel):
             n = btns_trk[k].keys()[0]
             lab = btns_trk[k].values()[0]
             self.btns_coord[n] = wx.Button(self, k, label=lab, size=wx.Size(45, 23))
-            self.btns_coord[n].SetToolTip(tips_trk[n-3])
+            self.btns_coord[n].SetToolTip(wx.ToolTip(tips_trk[n-3]))
             # Excepetion for event of button that set image coordinates
             if n == 6:
                 self.btns_coord[n].Bind(wx.EVT_BUTTON, self.OnSetImageCoordinates)
@@ -796,4 +796,4 @@ class MarkersPanel(wx.Panel):
         while len(selection) != self.lc.GetSelectedItemCount():
             index = self.lc.GetNextSelected(index)
             selection.append(index)
-        return selection
\ No newline at end of file
+        return selection
--
libgit2 0.21.2