diff --git a/.github/workflows/ci_workflows.yml b/.github/workflows/ci_workflows.yml
index 32078608..5dd6e124 100644
--- a/.github/workflows/ci_workflows.yml
+++ b/.github/workflows/ci_workflows.yml
@@ -24,26 +24,28 @@ jobs:
     with:
       display: true
       coverage: codecov
-      # The Linux PyQt 5.15 installation requires apt-getting its xcb deps and headless X11 display
+      # Linux PyQt 5.15 and 6.x installations require apt-getting xcb and EGL deps
+      # and headless X11 display
       libraries: |
         apt:
           - '^libxcb.*-dev'
           - libxkbcommon-x11-dev
+          - libegl1-mesa
 
       envs: |
         # Standard tests
         - linux: py37-test
         - linux: py38-test
-        - linux: py39-test
-        - linux: py310-test-dev
+        - linux: py39-test-pyqt6
+        - linux: py310-test-dev-pyqt6
 
         - macos: py38-test
         - macos: py39-test-dev
-        - macos: py310-test
+        - macos: py310-test-pyqt6
 
         - windows: py38-test
         - windows: py39-test-dev
-        - windows: py310-test
+        - windows: py310-test-pyqt6
 
   publish:
     needs: tests
diff --git a/codecov.yml b/codecov.yml
new file mode 100644
index 00000000..b976ba6f
--- /dev/null
+++ b/codecov.yml
@@ -0,0 +1,10 @@
+comment: off
+coverage:
+  status:
+    project:
+      default:
+        target: auto
+        # adjust accordingly based on how flaky your tests are
+        # this allows a 0.001% drop from the previous base commit coverage
+        # basically just to prevent counting zero changes as negative
+        threshold: 0.001%
diff --git a/glue_vispy_viewers/common/viewer_options.ui b/glue_vispy_viewers/common/viewer_options.ui
index 66df740a..f449a68a 100644
--- a/glue_vispy_viewers/common/viewer_options.ui
+++ b/glue_vispy_viewers/common/viewer_options.ui
@@ -138,14 +138,14 @@
    <item row="4" column="3" colspan="3">
     <widget class="QComboBox" name="combosel_y_att">
      <property name="sizeAdjustPolicy">
-      <enum>QComboBox::AdjustToMinimumContentsLength</enum>
+      <enum>QComboBox::AdjustToMinimumContentsLengthWithIcon</enum>
      </property>
     </widget>
    </item>
    <item row="7" column="3" colspan="3">
     <widget class="QComboBox" name="combosel_z_att">
      <property name="sizeAdjustPolicy">
-      <enum>QComboBox::AdjustToMinimumContentsLength</enum>
+      <enum>QComboBox::AdjustToMinimumContentsLengthWithIcon</enum>
      </property>
     </widget>
    </item>
@@ -236,7 +236,7 @@
    <item row="0" column="3" colspan="3">
     <widget class="QComboBox" name="combosel_x_att">
      <property name="sizeAdjustPolicy">
-      <enum>QComboBox::AdjustToMinimumContentsLength</enum>
+      <enum>QComboBox::AdjustToMinimumContentsLengthWithIcon</enum>
      </property>
     </widget>
    </item>
diff --git a/glue_vispy_viewers/isosurface/layer_style_widget.ui b/glue_vispy_viewers/isosurface/layer_style_widget.ui
index 941b38dd..39515a54 100644
--- a/glue_vispy_viewers/isosurface/layer_style_widget.ui
+++ b/glue_vispy_viewers/isosurface/layer_style_widget.ui
@@ -51,7 +51,7 @@
    <item row="0" column="1" colspan="3">
     <widget class="QComboBox" name="combosel_attribute">
      <property name="sizeAdjustPolicy">
-      <enum>QComboBox::AdjustToMinimumContentsLength</enum>
+      <enum>QComboBox::AdjustToMinimumContentsLengthWithIcon</enum>
      </property>
     </widget>
    </item>
diff --git a/glue_vispy_viewers/scatter/layer_style_widget.ui b/glue_vispy_viewers/scatter/layer_style_widget.ui
index 97f95f9e..e30e3f8c 100644
--- a/glue_vispy_viewers/scatter/layer_style_widget.ui
+++ b/glue_vispy_viewers/scatter/layer_style_widget.ui
@@ -98,7 +98,7 @@
           <item>
            <widget class="QComboBox" name="combosel_size_attribute">
             <property name="sizeAdjustPolicy">
-             <enum>QComboBox::AdjustToMinimumContentsLength</enum>
+             <enum>QComboBox::AdjustToMinimumContentsLengthWithIcon</enum>
             </property>
            </widget>
           </item>
@@ -260,7 +260,7 @@
           <item>
            <widget class="QComboBox" name="combosel_cmap_attribute">
             <property name="sizeAdjustPolicy">
-             <enum>QComboBox::AdjustToMinimumContentsLength</enum>
+             <enum>QComboBox::AdjustToMinimumContentsLengthWithIcon</enum>
             </property>
            </widget>
           </item>
@@ -346,7 +346,7 @@
           <item>
            <widget class="QColormapCombo" name="combodata_cmap">
             <property name="sizeAdjustPolicy">
-             <enum>QComboBox::AdjustToMinimumContentsLength</enum>
+             <enum>QComboBox::AdjustToMinimumContentsLengthWithIcon</enum>
             </property>
            </widget>
           </item>
@@ -456,7 +456,7 @@
         </rect>
        </property>
        <property name="sizeAdjustPolicy">
-        <enum>QComboBox::AdjustToMinimumContentsLength</enum>
+        <enum>QComboBox::AdjustToMinimumContentsLengthWithIcon</enum>
        </property>
       </widget>
       <widget class="QLabel" name="label_6">
@@ -488,7 +488,7 @@
         </rect>
        </property>
        <property name="sizeAdjustPolicy">
-        <enum>QComboBox::AdjustToMinimumContentsLength</enum>
+        <enum>QComboBox::AdjustToMinimumContentsLengthWithIcon</enum>
        </property>
       </widget>
       <widget class="QLabel" name="label_7">
@@ -520,7 +520,7 @@
         </rect>
        </property>
        <property name="sizeAdjustPolicy">
-        <enum>QComboBox::AdjustToMinimumContentsLength</enum>
+        <enum>QComboBox::AdjustToMinimumContentsLengthWithIcon</enum>
        </property>
       </widget>
       <widget class="QCheckBox" name="bool_zerr_visible">
@@ -551,7 +551,7 @@
         </rect>
        </property>
        <property name="sizeAdjustPolicy">
-        <enum>QComboBox::AdjustToMinimumContentsLength</enum>
+        <enum>QComboBox::AdjustToMinimumContentsLengthWithIcon</enum>
        </property>
       </widget>
       <widget class="QLabel" name="label_vector_y">
@@ -586,7 +586,7 @@
         </rect>
        </property>
        <property name="sizeAdjustPolicy">
-        <enum>QComboBox::AdjustToMinimumContentsLength</enum>
+        <enum>QComboBox::AdjustToMinimumContentsLengthWithIcon</enum>
        </property>
       </widget>
       <widget class="QCheckBox" name="bool_vector_visible">
@@ -700,7 +700,7 @@
         </rect>
        </property>
        <property name="sizeAdjustPolicy">
-        <enum>QComboBox::AdjustToMinimumContentsLength</enum>
+        <enum>QComboBox::AdjustToMinimumContentsLengthWithIcon</enum>
        </property>
       </widget>
       <widget class="QLabel" name="label_11">
diff --git a/glue_vispy_viewers/volume/layer_style_widget.ui b/glue_vispy_viewers/volume/layer_style_widget.ui
index 9a32bdf8..e328b89f 100644
--- a/glue_vispy_viewers/volume/layer_style_widget.ui
+++ b/glue_vispy_viewers/volume/layer_style_widget.ui
@@ -87,7 +87,7 @@
    <item row="0" column="1" colspan="2">
     <widget class="QComboBox" name="combosel_attribute">
      <property name="sizeAdjustPolicy">
-      <enum>QComboBox::AdjustToMinimumContentsLength</enum>
+      <enum>QComboBox::AdjustToMinimumContentsLengthWithIcon</enum>
      </property>
     </widget>
    </item>
diff --git a/glue_vispy_viewers/volume/volume_visual.py b/glue_vispy_viewers/volume/volume_visual.py
index 9038c3b4..e91fc04e 100644
--- a/glue_vispy_viewers/volume/volume_visual.py
+++ b/glue_vispy_viewers/volume/volume_visual.py
@@ -158,6 +158,8 @@ def __init__(self, n_volume_max=16, emulate_texture=False, bgcolor='white', reso
         # Set initial background color
         self.shared_program['u_bgcolor'] = Color(bgcolor).rgba
 
+        self._need_interpolation_update = False
+
         # Prevent additional attributes from being added
         try:
             self.freeze()
diff --git a/tox.ini b/tox.ini
index e652a6d5..c5a2a53f 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,6 +1,6 @@
 [tox]
 envlist =
-    py{37,38,39,310}-{test}-{dev}
+    py{37,38,39,310}-{test}-{dev}{,-pyqt6}
     codestyle
 requires = pip >= 18.0
            setuptools >= 30.3.0
@@ -12,7 +12,8 @@ passenv =
 changedir =
     test: .tmp/{envname}
 deps =
-    PyQt5==5.15.*
+    !pyqt6: PyQt5==5.15.*
+    pyqt6: PyQt6==6.4.*
     dev: glue-core @ git+https://github.com/glue-viz/glue
     dev: vispy @ git+https://github.com/vispy/vispy
 extras =