diff --git a/apps/expression_editor/controller.cpp b/apps/expression_editor/controller.cpp
index fdf9702cd..f19771346 100644
--- a/apps/expression_editor/controller.cpp
+++ b/apps/expression_editor/controller.cpp
@@ -12,9 +12,8 @@ Controller::Controller(Responder * parentResponder, ExpressionLayout * expressio
   m_view(parentResponder, expressionLayout, &m_cursor),
   m_expressionLayout(expressionLayout),
   m_resultLayout(nullptr)
-  //m_context((GlobalContext *)((AppsContainer *)(app()->container()))->globalContext())
 {
-  m_cursor.setPointedExpressionLayout(expressionLayout->editableChild(0));
+  m_cursor.setPointedExpressionLayout(expressionLayout);
 }
 
 void Controller::didBecomeFirstResponder() {
diff --git a/apps/expression_editor/expression_and_layout.cpp b/apps/expression_editor/expression_and_layout.cpp
index 36f09fcfb..24e0f3df4 100644
--- a/apps/expression_editor/expression_and_layout.cpp
+++ b/apps/expression_editor/expression_and_layout.cpp
@@ -39,7 +39,6 @@ ExpressionAndLayout::ExpressionAndLayout() {
 
   m_expression = Poincare::Expression::parse(expression);
   m_expressionLayout = new Poincare::HorizontalLayout();
-  m_expressionLayout->addChildAtIndex(new Poincare::EmptyVisibleLayout(), 0);
 }
 ExpressionAndLayout::~ExpressionAndLayout() {
   if (m_expressionLayout) {
diff --git a/poincare/include/poincare/dynamic_layout_hierarchy.h b/poincare/include/poincare/dynamic_layout_hierarchy.h
index a40a7fd13..4157d15fe 100644
--- a/poincare/include/poincare/dynamic_layout_hierarchy.h
+++ b/poincare/include/poincare/dynamic_layout_hierarchy.h
@@ -28,6 +28,7 @@ public:
   void addChildrenAtIndex(const ExpressionLayout * const * operands, int numberOfOperands, int indexForInsertion, bool removeEmptyChildren);
   bool addChildAtIndex(ExpressionLayout * operand, int index) override;
   void removeChildAtIndex(int index, bool deleteAfterRemoval) override;
+  void removePointedChildAtIndexAndMoveCursor(int index, bool deleteAfterRemoval, ExpressionLayoutCursor * cursor) override;
   void mergeChildrenAtIndex(DynamicLayoutHierarchy * eL, int index, bool removeEmptyChildren); // WITHOUT delete.
 
   bool isEmpty() const override;
diff --git a/poincare/include/poincare/expression_layout.h b/poincare/include/poincare/expression_layout.h
index 691f0f768..715ad8fbe 100644
--- a/poincare/include/poincare/expression_layout.h
+++ b/poincare/include/poincare/expression_layout.h
@@ -55,6 +55,7 @@ public:
   void detachChildren(); //Removes all children WITHOUT deleting them
   virtual bool addChildAtIndex(ExpressionLayout * child, int index) { return false; }
   virtual void removeChildAtIndex(int index, bool deleteAfterRemoval);
+  virtual void removePointedChildAtIndexAndMoveCursor(int index, bool deleteAfterRemoval, ExpressionLayoutCursor * cursor);
   virtual void backspaceAtCursor(ExpressionLayoutCursor * cursor);
 
   /* Tree navigation */
@@ -78,6 +79,7 @@ public:
   virtual bool isLeftBracket() const { return false; }
   virtual bool isRightBracket() const { return false; }
   virtual bool isEmpty() const { return false; }
+  virtual bool isMatrix() const { return false; }
   virtual char XNTChar() const;
 
 protected:
diff --git a/poincare/src/layout/bracket_left_right_layout.h b/poincare/src/layout/bracket_left_right_layout.h
index 4af7a09a3..98cf4e875 100644
--- a/poincare/src/layout/bracket_left_right_layout.h
+++ b/poincare/src/layout/bracket_left_right_layout.h
@@ -11,11 +11,11 @@ public:
   void invalidAllSizesPositionsAndBaselines() override;
   bool moveLeft(ExpressionLayoutCursor * cursor) override;
   bool moveRight(ExpressionLayoutCursor * cursor) override;
+protected:
   constexpr static KDCoordinate k_bracketWidth = 5;
   constexpr static KDCoordinate k_lineThickness = 1;
   constexpr static KDCoordinate k_widthMargin = 5;
   constexpr static KDCoordinate k_externWidthMargin = 2;
-protected:
   KDSize computeSize() override;
   KDCoordinate operandHeight();
   virtual void computeOperandHeight() = 0;
diff --git a/poincare/src/layout/dynamic_layout_hierarchy.cpp b/poincare/src/layout/dynamic_layout_hierarchy.cpp
index ce8c5fa28..7678abd18 100644
--- a/poincare/src/layout/dynamic_layout_hierarchy.cpp
+++ b/poincare/src/layout/dynamic_layout_hierarchy.cpp
@@ -1,5 +1,6 @@
 #include <poincare/dynamic_layout_hierarchy.h>
 #include "empty_visible_layout.h"
+#include <poincare/expression_layout_cursor.h>
 extern "C" {
 #include <assert.h>
 #include <stdlib.h>
@@ -113,9 +114,37 @@ void DynamicLayoutHierarchy::removeChildAtIndex(int index, bool deleteAfterRemov
   }
 }
 
+void DynamicLayoutHierarchy::removePointedChildAtIndexAndMoveCursor(int index, bool deleteAfterRemoval, ExpressionLayoutCursor * cursor) {
+  assert(index >= 0 && index < numberOfChildren());
+  assert(cursor->pointedExpressionLayout() == child(index));
+  if (numberOfChildren() == 1) {
+    if (m_parent) {
+      if (!deleteAfterRemoval) {
+        detachChild(editableChild(0));
+      }
+      m_parent->removePointedChildAtIndexAndMoveCursor(m_parent->indexOfChild(this), true, cursor);
+      return;
+    }
+    removeChildAtIndex(index, deleteAfterRemoval);
+    cursor->setPointedExpressionLayout(this);
+    cursor->setPosition(ExpressionLayoutCursor::Position::Left);
+    return;
+  }
+  removeChildAtIndex(index, deleteAfterRemoval);
+  if (index < numberOfChildren()) {
+    cursor->setPointedExpressionLayout(editableChild(index));
+    cursor->setPosition(ExpressionLayoutCursor::Position::Left);
+    return;
+  }
+  int indexOfNewPointedLayout = index - 1;
+  assert(indexOfNewPointedLayout >= 0);
+  assert(indexOfNewPointedLayout < numberOfChildren());
+  cursor->setPointedExpressionLayout(editableChild(indexOfNewPointedLayout));
+}
+
 bool DynamicLayoutHierarchy::isEmpty() const {
   if (m_numberOfChildren == 0
-      || (m_numberOfChildren == 1&& child(0)->isEmpty()))
+      || (m_numberOfChildren == 1 && child(0)->isEmpty()))
   {
     return true;
   }
diff --git a/poincare/src/layout/expression_layout.cpp b/poincare/src/layout/expression_layout.cpp
index 8587ea8e6..f79a62e0e 100644
--- a/poincare/src/layout/expression_layout.cpp
+++ b/poincare/src/layout/expression_layout.cpp
@@ -1,6 +1,7 @@
 #include <poincare/expression_layout.h>
 #include "empty_visible_layout.h"
 #include "horizontal_layout.h"
+#include "matrix_layout.h"
 #include <poincare/expression_layout_cursor.h>
 #include <assert.h>
 #include <stdlib.h>
@@ -230,10 +231,26 @@ void ExpressionLayout::removeChildAtIndex(int index, bool deleteAfterRemoval) {
   replaceChild(editableChild(index), new EmptyVisibleLayout(), deleteAfterRemoval);
 }
 
-void ExpressionLayout::backspaceAtCursor(ExpressionLayoutCursor * cursor) {
+void ExpressionLayout::removePointedChildAtIndexAndMoveCursor(int index, bool deleteAfterRemoval, ExpressionLayoutCursor * cursor) {
+  assert(index >= 0 && index < numberOfChildren());
+  assert(cursor->pointedExpressionLayout() == child(index));
+  removeChildAtIndex(index, deleteAfterRemoval);
+  if (index < numberOfChildren()) {
+    cursor->setPointedExpressionLayout(editableChild(index));
+    cursor->setPosition(ExpressionLayoutCursor::Position::Left);
+    return;
+  }
+  int indexOfNewPointedLayout = index - 1;
+  assert(indexOfNewPointedLayout >= 0);
+  assert(indexOfNewPointedLayout < numberOfChildren());
+  cursor->setPointedExpressionLayout(editableChild(indexOfNewPointedLayout));
+}
 
+void ExpressionLayout::backspaceAtCursor(ExpressionLayoutCursor * cursor) {
   int indexOfPointedExpression = indexOfChild(cursor->pointedExpressionLayout());
   if (indexOfPointedExpression >= 0) {
+    // Case: The pointed layout is a child.
+    // Point to the previous child, else to this.
     assert(cursor->position() == ExpressionLayoutCursor::Position::Left);
     if (indexOfPointedExpression == 0) {
       cursor->setPointedExpressionLayout(this);
@@ -245,14 +262,20 @@ void ExpressionLayout::backspaceAtCursor(ExpressionLayoutCursor * cursor) {
     return;
   }
   assert(cursor->pointedExpressionLayout() == this);
+  // Case: this is the pointed layout.
   if (m_parent == nullptr) {
+    // If there is no parent, return.
     return;
   }
   if (cursor->position() == ExpressionLayoutCursor::Position::Left) {
+    // Case: Left.
+    // Ask the parent.
     m_parent->backspaceAtCursor(cursor);
     return;
   }
   assert(cursor->position() == ExpressionLayoutCursor::Position::Right);
+  // Case: Right.
+  // If the layout has children, move to the last one.
   if (numberOfChildren() > 0) {
     cursor->setPointedExpressionLayout(editableChild(numberOfChildren()-1));
     cursor->performBackspace();
@@ -260,23 +283,16 @@ void ExpressionLayout::backspaceAtCursor(ExpressionLayoutCursor * cursor) {
   }
   int indexInParent = m_parent->indexOfChild(this);
   ExpressionLayout * previousParent = m_parent;
-  if (previousParent->numberOfChildren() == 1) {
+  // Case: Right.
+  // If the layout has no child and is only child, replace it with an empty layout.
+  /*if (previousParent->numberOfChildren() == 1) {
     ExpressionLayout * newLayout = new EmptyVisibleLayout();
     replaceWith(newLayout, true);
     cursor->setPointedExpressionLayout(newLayout);
     cursor->setPosition(ExpressionLayoutCursor::Position::Left);
     return;
-  }
-  previousParent->removeChildAtIndex(indexInParent, true);
-  if (indexInParent < previousParent->numberOfChildren()) {
-    cursor->setPointedExpressionLayout(previousParent->editableChild(indexInParent));
-    cursor->setPosition(ExpressionLayoutCursor::Position::Left);
-    return;
-  }
-  int indexOfNewPointedLayout = indexInParent - 1;
-  assert(indexOfNewPointedLayout >= 0);
-  assert(indexOfNewPointedLayout < previousParent->numberOfChildren());
-  cursor->setPointedExpressionLayout(previousParent->editableChild(indexOfNewPointedLayout));
+  }*/
+  previousParent->removePointedChildAtIndexAndMoveCursor(indexInParent, true, cursor);
 }
 
 char ExpressionLayout::XNTChar() const {
diff --git a/poincare/src/layout/grid_layout.cpp b/poincare/src/layout/grid_layout.cpp
index 39790b4d6..831c72f83 100644
--- a/poincare/src/layout/grid_layout.cpp
+++ b/poincare/src/layout/grid_layout.cpp
@@ -247,6 +247,22 @@ void GridLayout::addEmptyColumn(EmptyVisibleLayout::Color color) {
   }
 }
 
+void GridLayout::deleteRowAtIndex(int index) {
+  assert(index >= 0 && index < m_numberOfRows);
+  for (int i = 0; i < m_numberOfColumns; i++) {
+    DynamicLayoutHierarchy::removeChildAtIndex(index * m_numberOfColumns, true);
+  }
+  m_numberOfRows--;
+}
+
+void GridLayout::deleteColumnAtIndex(int index) {
+  assert(index >= 0 && index < m_numberOfColumns);
+  for (int i = (m_numberOfRows - 1) * m_numberOfColumns + index; i > -1; i-= m_numberOfColumns) {
+    DynamicLayoutHierarchy::removeChildAtIndex(i, true);
+  }
+  m_numberOfColumns--;
+}
+
 bool GridLayout::childIsLeftOfGrid(int index) const {
   assert(index >= 0 && index < m_numberOfRows*m_numberOfColumns);
   return columnAtChildIndex(index) == 0;
diff --git a/poincare/src/layout/grid_layout.h b/poincare/src/layout/grid_layout.h
index bee1df01a..dd03e309c 100644
--- a/poincare/src/layout/grid_layout.h
+++ b/poincare/src/layout/grid_layout.h
@@ -35,6 +35,8 @@ protected:
   KDPoint positionOfChild(ExpressionLayout * child) override;
   void addEmptyRow(EmptyVisibleLayout::Color color);
   void addEmptyColumn(EmptyVisibleLayout::Color color);
+  void deleteRowAtIndex(int index);
+  void deleteColumnAtIndex(int index);
   bool childIsRightOfGrid(int index) const;
   bool childIsBottomOfGrid(int index) const;
   int rowAtChildIndex(int index) const;
diff --git a/poincare/src/layout/horizontal_layout.cpp b/poincare/src/layout/horizontal_layout.cpp
index 62159aa03..2f75b68e8 100644
--- a/poincare/src/layout/horizontal_layout.cpp
+++ b/poincare/src/layout/horizontal_layout.cpp
@@ -61,7 +61,7 @@ void HorizontalLayout::privateReplaceChild(const ExpressionLayout * oldChild, Ex
     }
     // If the new layout is empty and it was the only horizontal layout child,
     // replace the horizontal layout with this empty layout (only if this is not
-    // the main layout, so only if the layout has a parent.
+    // the main layout, so only if the layout has a parent).
     if (m_parent) {
       if (cursor) {
         replaceWithAndMoveCursor(newChild, deleteOldChild, cursor);
diff --git a/poincare/src/layout/matrix_layout.cpp b/poincare/src/layout/matrix_layout.cpp
index 5ad8a03d5..eee2bcf42 100644
--- a/poincare/src/layout/matrix_layout.cpp
+++ b/poincare/src/layout/matrix_layout.cpp
@@ -17,6 +17,12 @@ ExpressionLayout * MatrixLayout::clone() const {
   return layout;
 }
 
+void MatrixLayout::replaceChild(const ExpressionLayout * oldChild, ExpressionLayout * newChild, bool deleteOldChild) {
+  int oldChildIndex = indexOfChild(const_cast<ExpressionLayout *>(oldChild));
+  GridLayout::replaceChild(oldChild, newChild, deleteOldChild);
+  childWasReplacedAtIndex(oldChildIndex);
+}
+
 void MatrixLayout::replaceChildAndMoveCursor(const ExpressionLayout * oldChild, ExpressionLayout * newChild, bool deleteOldChild, ExpressionLayoutCursor * cursor) {
   int oldChildIndex = indexOfChild(const_cast<ExpressionLayout *>(oldChild));
   int rowIndex = rowAtChildIndex(oldChildIndex);
@@ -59,6 +65,7 @@ int MatrixLayout::writeTextInBuffer(char * buffer, int bufferSize) const {
 }
 
 void MatrixLayout::newRowOrColumnAtIndex(int index) {
+  assert(index >= 0 && index < m_numberOfColumns*m_numberOfRows);
   bool shouldAddNewRow = GridLayout::childIsBottomOfGrid(index);
   int correspondingRow = rowAtChildIndex(index);
   // We need to compute this bool before modifying the layout.:w
@@ -73,7 +80,7 @@ void MatrixLayout::newRowOrColumnAtIndex(int index) {
       }
     }
     // Add a column of grey EmptyVisibleLayouts on the right.
-    GridLayout::addEmptyColumn(EmptyVisibleLayout::Color::Grey);
+    addEmptyColumn(EmptyVisibleLayout::Color::Grey);
   }
   if (shouldAddNewRow) {
     // Color the grey EmptyVisibleLayouts of the row in yellow.
@@ -84,7 +91,30 @@ void MatrixLayout::newRowOrColumnAtIndex(int index) {
       }
     }
     // Add a row of grey EmptyVisibleLayouts at the bottom.
-    GridLayout::addEmptyRow(EmptyVisibleLayout::Color::Grey);
+    addEmptyRow(EmptyVisibleLayout::Color::Grey);
+  }
+}
+
+void MatrixLayout::childWasReplacedAtIndex(int index) {
+  assert(index >= 0 && index < m_numberOfColumns*m_numberOfRows);
+  int rowIndex = rowAtChildIndex(index);
+  int columnIndex = columnAtChildIndex(index);
+  bool rowIsEmpty = isRowEmpty(rowIndex);
+  bool columnIsEmpty = isColumnEmpty(columnIndex);
+  if (rowIsEmpty && m_numberOfRows > 2) {
+    deleteRowAtIndex(rowIndex);
+  }
+  if (columnIsEmpty && m_numberOfColumns > 2) {
+    deleteColumnAtIndex(columnIndex);
+  }
+  if (!rowIsEmpty && !columnIsEmpty) {
+    ExpressionLayout * newChild = editableChild(index);
+    if (newChild->isEmpty()
+        && (childIsRightOfGrid(index)
+         || childIsBottomOfGrid(index)))
+    {
+      static_cast<EmptyVisibleLayout *>(newChild)->setColor(EmptyVisibleLayout::Color::Grey);
+    }
   }
 }
 
@@ -108,6 +138,7 @@ ExpressionLayout * dummyGridLayout = new GridLayout(children(), m_numberOfRows,
 }
 
 KDPoint MatrixLayout::positionOfChild(ExpressionLayout * child) {
+  assert(indexOfChild(child) > -1);
   BracketLeftLayout * dummyLeftBracket = new BracketLeftLayout();
   BracketRightLayout * dummyRightBracket = new BracketRightLayout();
 ExpressionLayout * dummyGridLayout = new GridLayout(children(), m_numberOfRows, m_numberOfColumns, true);
@@ -115,4 +146,24 @@ ExpressionLayout * dummyGridLayout = new GridLayout(children(), m_numberOfRows,
   return GridLayout::positionOfChild(child).translatedBy(dummyLayout.positionOfChild(dummyGridLayout));
 }
 
+bool MatrixLayout::isRowEmpty(int index) const {
+  assert(index >= 0 && index < m_numberOfRows);
+  for (int i = index * m_numberOfColumns; i < (index+1) * m_numberOfColumns; i++) {
+    if (!child(i)->isEmpty()) {
+      return false;
+    }
+  }
+  return true;
+}
+
+bool MatrixLayout::isColumnEmpty(int index) const {
+  assert(index >= 0 && index < m_numberOfColumns);
+  for (int i = index; i < m_numberOfRows * m_numberOfColumns; i+= m_numberOfColumns) {
+    if (!child(i)->isEmpty()) {
+      return false;
+    }
+  }
+  return true;
+}
+
 }
diff --git a/poincare/src/layout/matrix_layout.h b/poincare/src/layout/matrix_layout.h
index 83008d440..047753ca4 100644
--- a/poincare/src/layout/matrix_layout.h
+++ b/poincare/src/layout/matrix_layout.h
@@ -9,13 +9,19 @@ class MatrixLayout : public GridLayout {
 public:
   using GridLayout::GridLayout;
   ExpressionLayout * clone() const override;
+  void replaceChild(const ExpressionLayout * oldChild, ExpressionLayout * newChild, bool deleteOldChild = true) override;
   void replaceChildAndMoveCursor(const ExpressionLayout * oldChild, ExpressionLayout * newChild, bool deleteOldChild, ExpressionLayoutCursor * cursor) override;
   int writeTextInBuffer(char * buffer, int bufferSize) const override;
+  bool isMatrix() const override { return true; }
   void newRowOrColumnAtIndex(int index);
+  void childWasReplacedAtIndex(int index);
 protected:
   void render(KDContext * ctx, KDPoint p, KDColor expressionColor, KDColor backgroundColor) override;
   KDSize computeSize() override;
   KDPoint positionOfChild(ExpressionLayout * child) override;
+private:
+  bool isRowEmpty(int index) const;
+  bool isColumnEmpty(int index) const;
 };
 
 }