diff --git a/segmentator/__main__.py b/segmentator/__main__.py
index ef142fc9..0678625d 100644
--- a/segmentator/__main__.py
+++ b/segmentator/__main__.py
@@ -1,3 +1,4 @@
+#!/usr/bin/env python
 """Entry point.
 
 Mostly following this example:
diff --git a/segmentator/gui_utils.py b/segmentator/gui_utils.py
index c2e33892..f50957e2 100755
--- a/segmentator/gui_utils.py
+++ b/segmentator/gui_utils.py
@@ -1,3 +1,4 @@
+#!/usr/bin/env python
 """Functions covering the user interaction with the GUI."""
 
 # Part of the Segmentator library
diff --git a/segmentator/hist2d_counts.py b/segmentator/hist2d_counts.py
index 3c661785..80a22ca6 100644
--- a/segmentator/hist2d_counts.py
+++ b/segmentator/hist2d_counts.py
@@ -1,3 +1,4 @@
+#!/usr/bin/env python
 """Save 2D histogram image without displaying GUI."""
 
 # Part of the Segmentator library
diff --git a/segmentator/ncut_prepare.py b/segmentator/ncut_prepare.py
index c72dd771..eb4cd5a7 100644
--- a/segmentator/ncut_prepare.py
+++ b/segmentator/ncut_prepare.py
@@ -1,3 +1,4 @@
+#!/usr/bin/env python
 """Normalized graph cuts for segmentator (experimental).
 
 TODO: Replacing the functionality using scikit-learn?
diff --git a/segmentator/segmentator_main.py b/segmentator/segmentator_main.py
index beec5ac6..147e9775 100755
--- a/segmentator/segmentator_main.py
+++ b/segmentator/segmentator_main.py
@@ -1,3 +1,4 @@
+#!/usr/bin/env python
 """Processing input and plotting."""
 
 # Part of the Segmentator library
@@ -20,6 +21,8 @@
 from __future__ import division
 import numpy as np
 import config as cfg
+import matplotlib
+matplotlib.use('TkAgg')
 import matplotlib.pyplot as plt
 from matplotlib.colors import LogNorm
 from matplotlib.widgets import Slider, Button, LassoSelector
diff --git a/segmentator/segmentator_ncut.py b/segmentator/segmentator_ncut.py
index d42ed771..a134c9dd 100755
--- a/segmentator/segmentator_ncut.py
+++ b/segmentator/segmentator_ncut.py
@@ -1,3 +1,4 @@
+#!/usr/bin/env python
 """Processing input and plotting, for experimental ncut feature.
 
 Lots of code repetition, will be integrated better in the future.
@@ -23,6 +24,8 @@
 from __future__ import division
 import numpy as np
 import config as cfg
+import matplotlib
+matplotlib.use('TkAgg')
 import matplotlib.pyplot as plt
 from matplotlib.colors import LogNorm, ListedColormap, BoundaryNorm
 from matplotlib.widgets import Slider, Button, RadioButtons
diff --git a/segmentator/utils.py b/segmentator/utils.py
index 44947179..c63ae39b 100755
--- a/segmentator/utils.py
+++ b/segmentator/utils.py
@@ -1,3 +1,4 @@
+#!/usr/bin/env python
 """Some utility functions."""
 
 # Part of the Segmentator library