diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 169d720..d40e606 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -27,7 +27,7 @@ jobs:
         shell: bash
         run: |
           apt update
-          apt install -y libglu1-mesa
+          apt install -y libglu1-mesa libglib2.0-0 libfontconfig1
       -
         uses: actions/checkout@v2
       -
diff --git a/openmc_plotter/docks.py b/openmc_plotter/docks.py
index 1a4a11c..e63930e 100644
--- a/openmc_plotter/docks.py
+++ b/openmc_plotter/docks.py
@@ -412,7 +412,12 @@ def _bin_sort_val(bin):
                 else:
                     return bin
 
-            for bin in sorted(tally_filter.bins, key=_bin_sort_val):
+            if isinstance(tally_filter, openmc.EnergyFunctionFilter):
+                bins = [0]
+            else:
+                bins = tally_filter.bins
+
+            for bin in sorted(bins, key=_bin_sort_val):
                 item = QTreeWidgetItem(filter_item, [str(bin),])
                 if not spatial_filters:
                     item.setFlags(QtCore.Qt.ItemIsUserCheckable)
@@ -577,7 +582,11 @@ def updateFilters(self):
             filter_checked = f_item.checkState(0)
             if filter_checked != QtCore.Qt.Unchecked:
                 selected_bins = []
-                for idx, b in enumerate(f.bins):
+                if isinstance(f, openmc.EnergyFunctionFilter):
+                    bins = [0]
+                else:
+                    bins = f.bins
+                for idx, b in enumerate(bins):
                     b = b if not isinstance(b, Iterable) else tuple(b)
                     bin_checked = self.bin_map[(f, b)].checkState(0)
                     if bin_checked == QtCore.Qt.Checked:
diff --git a/openmc_plotter/plotmodel.py b/openmc_plotter/plotmodel.py
index f9f5cc7..4cea483 100644
--- a/openmc_plotter/plotmodel.py
+++ b/openmc_plotter/plotmodel.py
@@ -1,8 +1,8 @@
+from ast import literal_eval
 from collections import defaultdict
 import copy
 import itertools
 import threading
-from ast import literal_eval
 
 from PySide2.QtWidgets import QItemDelegate, QColorDialog, QLineEdit, QMessageBox
 from PySide2.QtCore import QAbstractTableModel, QModelIndex, Qt, QSize, QEvent
@@ -503,20 +503,29 @@ def _do_op(array, tally_value, ax=0):
         # applied to the mesh filter
         lower_left = mesh.lower_left
         upper_right = mesh.upper_right
+        width = mesh.width
+        dimension = mesh.dimension
         if hasattr(mesh_filter, 'translation') and mesh_filter.translation is not None:
             lower_left += mesh_filter.translation
             upper_right += mesh_filter.translation
 
+        # For 2D meshes, add an extra z dimension
+        if len(mesh.dimension) == 2:
+            lower_left = np.hstack((lower_left, -1e50))
+            upper_right = np.hstack((upper_right, 1e50))
+            width = np.hstack((width, 2e50))
+            dimension = np.hstack((dimension, 1))
+
         # reduce data to the visible slice of the mesh values
-        k = int((view.origin[ax] - lower_left[ax]) // mesh.width[ax])
+        k = int((view.origin[ax] - lower_left[ax]) // width[ax])
 
         # setup slice
         data_slice = [None, None, None]
-        data_slice[h_ind] = slice(mesh.dimension[h_ind])
-        data_slice[v_ind] = slice(mesh.dimension[v_ind])
+        data_slice[h_ind] = slice(dimension[h_ind])
+        data_slice[v_ind] = slice(dimension[v_ind])
         data_slice[ax] = k
 
-        if k < 0 or k > mesh.dimension[ax]:
+        if k < 0 or k > dimension[ax]:
             return (None, None, None, None)
 
         # move mesh axes to the end of the filters
@@ -524,7 +533,7 @@ def _do_op(array, tally_value, ax=0):
         data = np.moveaxis(data, filter_idx, -1)
 
         # reshape data (with zyx ordering for mesh data)
-        data = data.reshape(data.shape[:-1] + tuple(mesh.dimension[::-1]))
+        data = data.reshape(data.shape[:-1] + tuple(dimension[::-1]))
         data = data[..., data_slice[2], data_slice[1], data_slice[0]]
 
         # sum over the rest of the tally filters
diff --git a/pytest.ini b/pytest.ini
index 818dfa8..af65033 100644
--- a/pytest.ini
+++ b/pytest.ini
@@ -2,5 +2,5 @@
 qt_api=pyside2
 python_files = test*.py
 python_classes = NoThanks
-filter_warnings = ignore::UserWarning
-addopts = -rs
\ No newline at end of file
+filterwarnings = ignore::UserWarning
+addopts = -rs
diff --git a/tests/setup_test/test.py b/tests/setup_test/test.py
index f017d59..5a711d1 100644
--- a/tests/setup_test/test.py
+++ b/tests/setup_test/test.py
@@ -1,5 +1,3 @@
-import openmc.lib
-
 from openmc_plotter.main_window import MainWindow, _openmcReload
 
 def test_window(qtbot):