diff -r e81f4ad53efd -r 65b4741b302d src/mainwindow.ui
--- a/src/mainwindow.ui	Sat Apr 08 16:59:55 2023 +0300
+++ b/src/mainwindow.ui	Sat Apr 08 21:48:49 2023 +0300
@@ -7,7 +7,7 @@
     <x>0</x>
     <y>0</y>
     <width>959</width>
-    <height>600</height>
+    <height>695</height>
    </rect>
   </property>
   <property name="dockNestingEnabled">
@@ -45,7 +45,7 @@
      <x>0</x>
      <y>0</y>
      <width>959</width>
-     <height>29</height>
+     <height>38</height>
     </rect>
    </property>
    <widget class="QMenu" name="menuFile">
@@ -265,6 +265,54 @@
    <addaction name="actionGridCoarse"/>
    <addaction name="actionAdjustGridToView"/>
   </widget>
+  <widget class="QDockWidget" name="dockWidget">
+   <property name="features">
+    <set>QDockWidget::DockWidgetFloatable|QDockWidget::DockWidgetMovable</set>
+   </property>
+   <property name="windowTitle">
+    <string>Grid matrix</string>
+   </property>
+   <attribute name="dockWidgetArea">
+    <number>2</number>
+   </attribute>
+   <widget class="QWidget" name="dockWidgetContents_4">
+    <layout class="QVBoxLayout" name="verticalLayout_5">
+     <item>
+      <layout class="QHBoxLayout" name="horizontalLayout">
+       <item>
+        <widget class="MatrixEditor" name="gridMatrix"/>
+       </item>
+       <item>
+        <spacer name="horizontalSpacer">
+         <property name="orientation">
+          <enum>Qt::Horizontal</enum>
+         </property>
+         <property name="sizeHint" stdset="0">
+          <size>
+           <width>40</width>
+           <height>20</height>
+          </size>
+         </property>
+        </spacer>
+       </item>
+      </layout>
+     </item>
+     <item>
+      <spacer name="verticalSpacer">
+       <property name="orientation">
+        <enum>Qt::Vertical</enum>
+       </property>
+       <property name="sizeHint" stdset="0">
+        <size>
+         <width>20</width>
+         <height>40</height>
+        </size>
+       </property>
+      </spacer>
+     </item>
+    </layout>
+   </widget>
+  </widget>
   <action name="actionQuit">
    <property name="icon">
     <iconset resource="../resources.qrc">
@@ -547,6 +595,13 @@
    </property>
   </action>
  </widget>
+ <customwidgets>
+  <customwidget>
+   <class>MatrixEditor</class>
+   <extends>QWidget</extends>
+   <header>widgets/matrixeditor.h</header>
+  </customwidget>
+ </customwidgets>
  <resources>
   <include location="../resources.qrc"/>
   <include location="../resources.qrc"/>