diff -r 5d201ee4a9c3 -r b05af0bab735 src/mainwindow.ui
--- a/src/mainwindow.ui	Tue Jun 07 01:37:26 2022 +0300
+++ b/src/mainwindow.ui	Tue Jun 07 20:44:19 2022 +0300
@@ -16,10 +16,19 @@
   <widget class="QWidget" name="centralwidget">
    <layout class="QVBoxLayout" name="verticalLayout">
     <item>
-     <widget class="QTabWidget" name="tabs">
+     <widget class="QMdiArea" name="mdiArea">
+      <property name="viewMode">
+       <enum>QMdiArea::TabbedView</enum>
+      </property>
+      <property name="documentMode">
+       <bool>true</bool>
+      </property>
       <property name="tabsClosable">
        <bool>true</bool>
       </property>
+      <property name="tabsMovable">
+       <bool>true</bool>
+      </property>
      </widget>
     </item>
    </layout>
@@ -30,7 +39,7 @@
      <x>0</x>
      <y>0</y>
      <width>800</width>
-     <height>27</height>
+     <height>22</height>
     </rect>
    </property>
    <widget class="QMenu" name="menuFile">