diff --git a/src/hyperctui/autonomous_reconstruction/select_tof_regions.py b/src/hyperctui/autonomous_reconstruction/select_tof_regions.py
index 34b6448..6edf547 100644
--- a/src/hyperctui/autonomous_reconstruction/select_tof_regions.py
+++ b/src/hyperctui/autonomous_reconstruction/select_tof_regions.py
@@ -26,6 +26,8 @@ class SelectTofRegions(QMainWindow):
 
     top_roi_id = None
 
+    ok_clicked = False
+
     # used in case the value entered by the user are not valid
     previous_distance_source_detector = None
     previous_detector_offset = None
@@ -47,6 +49,7 @@ def __init__(self, parent=None):
         self.ui = load_ui(ui_full_path, baseinstance=self)
         self.setWindowTitle("Select TOF regions")
 
+        self.parent.backup_tof_regions = self.parent.tof_regions
         self.initialization()
         self.load_time_spectra()
         self.calculate_lambda_axis()
@@ -370,10 +373,20 @@ def regions_manually_moved(self):
         # self.update_evaluation_regions_dict()
 
     def accept(self):
+        self.ok_clicked = True
         self.save_table()
         self.parent.update_autonomous_widgets()
         self.close()
 
+    def cancel(self):
+        self.close()
+
+    def closeEvent(self, a0):
+        if self.ok_clicked:
+            pass
+        else:
+            self.parent.tof_regions = self.parent.backup_tof_regions
+
     @staticmethod
     def sort(value1: float, value2: float):
         minimum_value = np.min([value1, value2])
diff --git a/src/hyperctui/hyperctui.py b/src/hyperctui/hyperctui.py
index cd4e778..b495ccc 100644
--- a/src/hyperctui/hyperctui.py
+++ b/src/hyperctui/hyperctui.py
@@ -131,6 +131,8 @@ class HyperCTui(QMainWindow):
                              EvaluationRegionKeys.id: None,
                              EvaluationRegionKeys.label_id: None,
                              }
+    # this will be a copy of evaluation regions used when user exit the view without using OK button
+    backup_evaluation_regions = None
 
     # tof selection regions
     tof_regions = OrderedDict()
@@ -155,6 +157,10 @@ class HyperCTui(QMainWindow):
                       EvaluationRegionKeys.id: None,
                       EvaluationRegionKeys.label_id: None
                       }
+
+    # this will be a copy of evaluation regions used when user exit the view without using OK button
+    backup_tof_regions = None
+
     # dictionary that will store the 3D images (used in the TOF region selection)
 
     image_data = {SessionKeys.image_0_degree: None,
diff --git a/src/hyperctui/ui/select_tof_regions.ui b/src/hyperctui/ui/select_tof_regions.ui
index 074f67f..84a9d6f 100644
--- a/src/hyperctui/ui/select_tof_regions.ui
+++ b/src/hyperctui/ui/select_tof_regions.ui
@@ -261,6 +261,13 @@
     </item>
     <item>
      <layout class="QHBoxLayout" name="horizontalLayout">
+      <item>
+       <widget class="QPushButton" name="pushButton_2">
+        <property name="text">
+         <string>Cancel</string>
+        </property>
+       </widget>
+      </item>
       <item>
        <spacer name="horizontalSpacer">
         <property name="orientation">
@@ -306,8 +313,8 @@
    <slot>projections_changed()</slot>
    <hints>
     <hint type="sourcelabel">
-     <x>570</x>
-     <y>76</y>
+     <x>546</x>
+     <y>87</y>
     </hint>
     <hint type="destinationlabel">
      <x>734</x>
@@ -338,8 +345,8 @@
    <slot>instrument_settings_changed()</slot>
    <hints>
     <hint type="sourcelabel">
-     <x>284</x>
-     <y>443</y>
+     <x>319</x>
+     <y>562</y>
     </hint>
     <hint type="destinationlabel">
      <x>730</x>
@@ -354,8 +361,8 @@
    <slot>instrument_settings_changed()</slot>
    <hints>
     <hint type="sourcelabel">
-     <x>581</x>
-     <y>441</y>
+     <x>587</x>
+     <y>562</y>
     </hint>
     <hint type="destinationlabel">
      <x>729</x>
@@ -370,8 +377,8 @@
    <slot>table_changed()</slot>
    <hints>
     <hint type="sourcelabel">
-     <x>386</x>
-     <y>617</y>
+     <x>526</x>
+     <y>940</y>
     </hint>
     <hint type="destinationlabel">
      <x>719</x>
@@ -386,8 +393,8 @@
    <slot>accept()</slot>
    <hints>
     <hint type="sourcelabel">
-     <x>673</x>
-     <y>794</y>
+     <x>666</x>
+     <y>1030</y>
     </hint>
     <hint type="destinationlabel">
      <x>569</x>
@@ -395,11 +402,28 @@
     </hint>
    </hints>
   </connection>
+  <connection>
+   <sender>pushButton_2</sender>
+   <signal>clicked()</signal>
+   <receiver>MainWindow</receiver>
+   <slot>cancel()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>56</x>
+     <y>1008</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>151</x>
+     <y>1010</y>
+    </hint>
+   </hints>
+  </connection>
  </connections>
  <slots>
   <slot>table_changed()</slot>
   <slot>projections_changed()</slot>
   <slot>instrument_settings_changed()</slot>
   <slot>accept()</slot>
+  <slot>cancel()</slot>
  </slots>
 </ui>