diff --git a/poincare/include/poincare/expression.h b/poincare/include/poincare/expression.h
index e5a48e375..0413eed06 100644
--- a/poincare/include/poincare/expression.h
+++ b/poincare/include/poincare/expression.h
@@ -150,7 +150,6 @@ private:
   /* Evaluation Engine */
   virtual Evaluation<float> * privateEvaluate(SinglePrecision p, Context& context, AngleUnit angleUnit) const = 0;
   virtual Evaluation<double> * privateEvaluate(DoublePrecision p, Context& context, AngleUnit angleUnit) const = 0;
-  void recursivelySetAsParentOfChildren();
 private:
   Expression * m_parent;
 };
diff --git a/poincare/include/poincare/matrix_data.h b/poincare/include/poincare/matrix_data.h
index 5dc3d1eb8..5390c7791 100644
--- a/poincare/include/poincare/matrix_data.h
+++ b/poincare/include/poincare/matrix_data.h
@@ -12,7 +12,7 @@ class Complex;
 class MatrixData {
 public:
   MatrixData(ListData * listData, bool clone);
-  MatrixData(Expression ** newOperands, int numberOfOperands, int m_numberOfRows, int m_numberOfColumns, bool cloneOperands);
+  MatrixData(Expression ** newOperands, int numberOfOperands, int m_numberOfRows, int m_numberOfColumns, bool cloneOperands, Expression * parent);
   ~MatrixData();
   MatrixData(const MatrixData& other) = delete;
   MatrixData(MatrixData&& other) = delete;
diff --git a/poincare/src/complex_matrix.cpp b/poincare/src/complex_matrix.cpp
index f76508af0..55abfb82b 100644
--- a/poincare/src/complex_matrix.cpp
+++ b/poincare/src/complex_matrix.cpp
@@ -21,6 +21,7 @@ ComplexMatrix<T>::ComplexMatrix(const Complex<T> * complexes, int numberOfRows,
   m_values = new Complex<T>[numberOfRows*numberOfColumns];
   for (int i = 0; i < numberOfRows*numberOfColumns; i++) {
     m_values[i] = complexes[i];
+    m_values[i].setParent(this);
   }
 }
 
diff --git a/poincare/src/expression.cpp b/poincare/src/expression.cpp
index d18ab884d..26c82b4ab 100644
--- a/poincare/src/expression.cpp
+++ b/poincare/src/expression.cpp
@@ -32,9 +32,6 @@ Expression * Expression::parse(char const * string) {
   }
   poincare_expression_yy_delete_buffer(buf);
 
-  if (expression) {
-    expression->recursivelySetAsParentOfChildren();
-  }
   return expression;
 }
 
@@ -152,18 +149,6 @@ template<typename T> T Expression::epsilon() {
   return epsilon;
 }
 
-void Expression::recursivelySetAsParentOfChildren() {
-  if (this->type() == Type::Complex) {
-    // TODO: this case should be useless once complex is a leaf expression!
-    return;
-  }
-  for (int i=0; i<numberOfOperands(); i++) {
-    Expression * child = const_cast<Expression *>(operand(i));
-    child->setParent(this);
-    child->recursivelySetAsParentOfChildren();
-  }
-}
-
 }
 
 template Poincare::Evaluation<double> * Poincare::Expression::evaluate<double>(Context& context, AngleUnit angleUnit) const;
diff --git a/poincare/src/expression_matrix.cpp b/poincare/src/expression_matrix.cpp
index f394b67b7..eb0479ed9 100644
--- a/poincare/src/expression_matrix.cpp
+++ b/poincare/src/expression_matrix.cpp
@@ -18,7 +18,7 @@ ExpressionMatrix::ExpressionMatrix(MatrixData * matrixData) :
 
 ExpressionMatrix::ExpressionMatrix(Expression ** newOperands, int numberOfOperands, int numberOfRows, int numberOfColumns, bool cloneOperands)
 {
-  m_matrixData = new MatrixData(newOperands, numberOfOperands, numberOfRows, numberOfColumns, cloneOperands);
+  m_matrixData = new MatrixData(newOperands, numberOfOperands, numberOfRows, numberOfColumns, cloneOperands, this);
 }
 
 ExpressionMatrix::~ExpressionMatrix() {
diff --git a/poincare/src/matrix_data.cpp b/poincare/src/matrix_data.cpp
index 0489429be..1cb1e63ba 100644
--- a/poincare/src/matrix_data.cpp
+++ b/poincare/src/matrix_data.cpp
@@ -23,7 +23,7 @@ MatrixData::MatrixData(ListData * listData, bool clone) :
   }
 }
 
-MatrixData::MatrixData(Expression ** newOperands, int numberOfOperands, int numberOfRows, int numberOfColumns, bool cloneOperands) :
+MatrixData::MatrixData(Expression ** newOperands, int numberOfOperands, int numberOfRows, int numberOfColumns, bool cloneOperands, Expression * parent) :
   m_numberOfRows(numberOfRows),
   m_numberOfColumns(numberOfColumns)
 {
@@ -35,6 +35,7 @@ MatrixData::MatrixData(Expression ** newOperands, int numberOfOperands, int numb
     } else {
       m_operands[i] = i < numberOfOperands ? newOperands[i] : defaultExpression();
     }
+    const_cast<Expression *>(m_operands[i])->setParent(parent);
   }
 }
 
diff --git a/poincare/src/static_hierarchy.cpp b/poincare/src/static_hierarchy.cpp
index 1db3bbb92..acb42998c 100644
--- a/poincare/src/static_hierarchy.cpp
+++ b/poincare/src/static_hierarchy.cpp
@@ -44,12 +44,12 @@ void StaticHierarchy<T>::build(const Expression * const * operands, int numberOf
   assert(numberOfOperands <= T);
   for (int i=0; i < numberOfOperands; i++) {
     assert(operands[i] != nullptr);
-    const_cast<Expression *>(operands[i])->setParent(this);
     if (cloneOperands) {
       m_operands[i] = operands[i]->clone();
     } else {
       m_operands[i] = operands[i];
     }
+    const_cast<Expression *>(m_operands[i])->setParent(this);
   }
 }