diff --git a/sashimi/gui/camera_gui.py b/sashimi/gui/camera_gui.py
index afab32f5..a348481b 100644
--- a/sashimi/gui/camera_gui.py
+++ b/sashimi/gui/camera_gui.py
@@ -65,7 +65,7 @@ class ViewingWidget(QWidget):
 
     _DELAY_REFRESH_COUNT = 10
 
-    def __init__(self, state: State, timer: QTimer, style: str):
+    def __init__(self, state: State, timer: QTimer, style: str, viewer: napari.Viewer):
         super().__init__()
         self.state = state
         timer.timeout.connect(self.refresh)
@@ -86,7 +86,7 @@ def __init__(self, state: State, timer: QTimer, style: str):
         s = self.get_fullframe_size()
         self.image_shape = (1, s, s)
 
-        self.viewer = napari.Viewer(show=False)
+        self.viewer = viewer
         # setting napari style to sashimi's
         self.viewer.window.qt_viewer.setStyleSheet(style)
 
diff --git a/sashimi/gui/main_gui.py b/sashimi/gui/main_gui.py
index 17aa992e..7c9232c6 100644
--- a/sashimi/gui/main_gui.py
+++ b/sashimi/gui/main_gui.py
@@ -28,17 +28,15 @@ def __init__(self, widget=None, layout=None, title=""):
 
 
 class MainWindow(QMainWindow):
-    def __init__(self, st: State, style: str):
+    def __init__(self, st: State, style: str, viewer):
         super().__init__()
         self.st = st
         self.timer = QTimer()
-        self.showMaximized()
 
         self.wid_settings_tree = SavingSettingsWidget(st)
         self.wid_settings_tree.sig_params_loaded.connect(self.refresh_param_values)
-
         self.wid_status = StatusWidget(st, self.timer)
-        self.wid_display = ViewingWidget(st, self.timer, style)
+        self.wid_display = ViewingWidget(st, self.timer, style, viewer)
         self.wid_save_options = SaveWidget(st, self.timer)
         self.wid_laser = LightSourceWidget(st, self.timer)
         self.wid_scan = PlanarScanningWidget(st)
@@ -85,6 +83,7 @@ def __init__(self, st: State, style: str):
         self.timer.start()
         self.timer.timeout.connect(self.check_end_experiment)
         self.setup_menu_bar()
+        self.showMaximized()
 
         self.refresh_param_values()
 
diff --git a/sashimi/main.py b/sashimi/main.py
index 700c902a..c65b2958 100644
--- a/sashimi/main.py
+++ b/sashimi/main.py
@@ -6,6 +6,7 @@
 from sashimi.config import cli_edit_config
 from sashimi.state import State
 from pathlib import Path
+import napari
 
 
 @click.command()
@@ -16,13 +17,13 @@ def main(scopeless, scanning, **kwargs):
     cli_edit_config("scanning", scanning)
 
     # TODO configure logging with CLI
-
     app = QApplication([])
+    viewer = napari.Viewer(show=False)
     style = qdarkstyle.load_stylesheet_pyqt5()
     app.setStyleSheet(style)
     app.setApplicationName("Sashimi")
-    st = State()
-    main_window = MainWindow(st, style)
+    state = State()
+    main_window = MainWindow(state, style, viewer)
     icon_dir = (Path(__file__).parents[0]).resolve() / "icons/main_icon.png"
     app.setWindowIcon(QIcon(str(icon_dir)))  # PyQt does not accept Path
     main_window.show()
diff --git a/tests/test_gui.py b/tests/test_gui.py
index 981536be..a79886ff 100644
--- a/tests/test_gui.py
+++ b/tests/test_gui.py
@@ -3,6 +3,7 @@
 import qdarkstyle
 from PyQt5.QtCore import Qt
 from split_dataset import SplitDataset
+import napari
 
 
 class MockEvt:
@@ -11,9 +12,10 @@ def accept(self):
 
 
 def test_main(qtbot, temp_path):
-    st = State()
+    viewer = napari.Viewer(show=False)
+    state = State()
     style = qdarkstyle.load_stylesheet_pyqt5()
-    main_window = MainWindow(st, style)
+    main_window = MainWindow(state, style, viewer)
     main_window.show()
     qtbot.wait(300)
 
@@ -23,9 +25,9 @@ def test_main(qtbot, temp_path):
     main_window.wid_status.setCurrentIndex(3)
 
     # Manually update new directory (to avoid nasty pop up window for filesystem):
-    st.save_settings.save_dir = str(temp_path)
+    state.save_settings.save_dir = str(temp_path)
     main_window.wid_save_options.set_locationbutton()
-    st.send_scansave_settings()
+    state.send_scansave_settings()
 
     # Wait to send and receive parameters:
     qtbot.wait(10000)