diff --git a/CHANGELOG b/CHANGELOG
index f63d71b..c28811f 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -4,6 +4,7 @@
  - fix: polygon filters were not stored correctly in log mode
  - fix: several issues related to contour plots, contour spacing,
    and log-scales
+ - fix: subclass MDSubWindow and catch closeEvent (#29)
  - enh+docs: make Young's modulus computation more user convenient and
    update the section in the docs
  - docs: finish first draft of documentation
diff --git a/shapeout2/gui/main.py b/shapeout2/gui/main.py
index 326cf47..bfbebe9 100644
--- a/shapeout2/gui/main.py
+++ b/shapeout2/gui/main.py
@@ -20,6 +20,7 @@
 from . import pipeline_plot
 from . import quick_view
 from . import update
+from . import widgets
 
 from .. import pipeline
 from .. import session
@@ -359,15 +360,12 @@ def add_plot_window(self, plot_id):
             sub = self.subwindows_plots[plot_id]
         else:
             # create subwindow
-            sub = QtWidgets.QMdiSubWindow(self)
+            sub = widgets.MDISubWindowWOButtons(self)
             pw = pipeline_plot.PipelinePlot(parent=sub,
                                             pipeline=self.pipeline,
                                             plot_id=plot_id)
             self.plots_changed.connect(pw.update_content)
             pw.update_content()
-            sub.setSystemMenu(None)
-            sub.setWindowFlags(QtCore.Qt.CustomizeWindowHint
-                               | QtCore.Qt.WindowTitleHint)
             sub.setWidget(pw)
             self.mdiArea.addSubWindow(sub)
             self.subwindows_plots[plot_id] = sub
@@ -375,12 +373,9 @@ def add_plot_window(self, plot_id):
         sub.show()
 
     def init_analysis_view(self):
-        sub = QtWidgets.QMdiSubWindow(self)
+        sub = widgets.MDISubWindowWOButtons(self)
         self.widget_ana_view = analysis.AnalysisView()
         self.subwindows["analysis_view"] = sub
-        sub.setSystemMenu(None)
-        sub.setWindowFlags(QtCore.Qt.CustomizeWindowHint
-                           | QtCore.Qt.WindowTitleHint)
         sub.setWidget(self.widget_ana_view)
         sub.hide()
         self.mdiArea.addSubWindow(sub)
@@ -390,16 +385,13 @@ def init_analysis_view(self):
             self.on_quickview_refresh)
 
     def init_quick_view(self):
-        sub = QtWidgets.QMdiSubWindow(self)
+        sub = widgets.MDISubWindowWOButtons(self)
         self.widget_quick_view = quick_view.QuickView()
         sub.setWidget(self.widget_quick_view)
         self.toolButton_quick_view.clicked.connect(self.on_quickview)
         self.subwindows["quick_view"] = sub
         # signals
         self.block_matrix.quickviewed.connect(self.on_quickview_show_dataset)
-        sub.setSystemMenu(None)
-        sub.setWindowFlags(QtCore.Qt.CustomizeWindowHint
-                           | QtCore.Qt.WindowTitleHint)
         sub.hide()
         self.mdiArea.addSubWindow(sub)
 
diff --git a/shapeout2/gui/widgets/__init__.py b/shapeout2/gui/widgets/__init__.py
index 8c9003b..15db857 100644
--- a/shapeout2/gui/widgets/__init__.py
+++ b/shapeout2/gui/widgets/__init__.py
@@ -1,6 +1,7 @@
 from .colorbar_widget import ColorBarWidget  # noqa: F401
 from .double_spin_box_nan import DoubleSpinBoxNan  # noqa: F401
 from .key_value_table_widget import KeyValueTableWidget  # noqa: F401
+from .mdi_subwindow_wo_close import MDISubWindowWOButtons  # noqa: F401
 from .qrangeslider import QRangeSlider  # noqa: F401
 from .rangecontrol import RangeControl  # noqa: F401
 from .simple_image_view import SimpleImageView  # noqa: F401
diff --git a/shapeout2/gui/widgets/mdi_subwindow_wo_close.py b/shapeout2/gui/widgets/mdi_subwindow_wo_close.py
new file mode 100644
index 0000000..fb947f5
--- /dev/null
+++ b/shapeout2/gui/widgets/mdi_subwindow_wo_close.py
@@ -0,0 +1,12 @@
+from PyQt5 import QtCore, QtWidgets
+
+
+class MDISubWindowWOButtons(QtWidgets.QMdiSubWindow):
+    def __init__(self, *args, **kwargs):
+        super(MDISubWindowWOButtons, self).__init__(*args, **kwargs)
+        self.setSystemMenu(None)
+        self.setWindowFlags(QtCore.Qt.CustomizeWindowHint
+                            | QtCore.Qt.WindowTitleHint)
+
+    def closeEvent(self, event):
+        event.ignore()