diff --git a/apps/regression/app.cpp b/apps/regression/app.cpp
index 783b86fdd..c964d55ce 100644
--- a/apps/regression/app.cpp
+++ b/apps/regression/app.cpp
@@ -47,6 +47,7 @@ App::Descriptor * App::Snapshot::descriptor() {
 
 void App::Snapshot::tidy() {
   m_store.setDelegate(nullptr);
+  m_store.tidy();
 }
 
 App::App(Container * container, Snapshot * snapshot) :
diff --git a/apps/regression/model/cubic_model.cpp b/apps/regression/model/cubic_model.cpp
index 66752cd1d..a1c90448b 100644
--- a/apps/regression/model/cubic_model.cpp
+++ b/apps/regression/model/cubic_model.cpp
@@ -9,8 +9,7 @@ using namespace Shared;
 namespace Regression {
 
 LayoutReference CubicModel::layout() {
-  static LayoutReference layout;
-  if (layout.isUninitialized()) {
+  if (m_layout.isUninitialized()) {
     const LayoutReference layoutChildren[] = {
       CharLayoutRef('a', KDText::FontSize::Small),
       CharLayoutRef(Ion::Charset::MiddleDot, KDText::FontSize::Small),
@@ -34,9 +33,9 @@ LayoutReference CubicModel::layout() {
       CharLayoutRef('+', KDText::FontSize::Small),
       CharLayoutRef('d', KDText::FontSize::Small),
     };
-    layout = HorizontalLayoutRef(layoutChildren, 15);
+    m_layout = HorizontalLayoutRef(layoutChildren, 15);
   }
-  return layout;
+  return m_layout;
 }
 
 Expression CubicModel::simplifiedExpression(double * modelCoefficients, Poincare::Context * context) {
diff --git a/apps/regression/model/exponential_model.cpp b/apps/regression/model/exponential_model.cpp
index 7572a31f8..7030e18a8 100644
--- a/apps/regression/model/exponential_model.cpp
+++ b/apps/regression/model/exponential_model.cpp
@@ -7,8 +7,7 @@ using namespace Poincare;
 namespace Regression {
 
 LayoutReference ExponentialModel::layout() {
-  static LayoutReference layout;
-  if (layout.isUninitialized()) {
+  if (m_layout.isUninitialized()) {
     const LayoutReference layoutChildren[] = {
       CharLayoutRef('a', KDText::FontSize::Small),
       CharLayoutRef(Ion::Charset::MiddleDot, KDText::FontSize::Small),
@@ -22,9 +21,9 @@ LayoutReference ExponentialModel::layout() {
           VerticalOffsetLayoutNode::Type::Superscript
         )
     };
-    layout = HorizontalLayoutRef(layoutChildren, 4);
+    m_layout = HorizontalLayoutRef(layoutChildren, 4);
   }
-  return layout;
+  return m_layout;
 }
 
 double ExponentialModel::evaluate(double * modelCoefficients, double x) const {
diff --git a/apps/regression/model/linear_model.cpp b/apps/regression/model/linear_model.cpp
index 7e4674628..f8dbe2b8b 100644
--- a/apps/regression/model/linear_model.cpp
+++ b/apps/regression/model/linear_model.cpp
@@ -8,8 +8,7 @@ using namespace Poincare;
 namespace Regression {
 
 LayoutReference LinearModel::layout() {
-  static LayoutReference layout;
-  if (layout.isUninitialized()) {
+  if (m_layout.isUninitialized()) {
     const LayoutReference layoutChildren[] = {
       CharLayoutRef('a', KDText::FontSize::Small),
       CharLayoutRef(Ion::Charset::MiddleDot, KDText::FontSize::Small),
@@ -17,9 +16,9 @@ LayoutReference LinearModel::layout() {
       CharLayoutRef('+', KDText::FontSize::Small),
       CharLayoutRef('b', KDText::FontSize::Small),
     };
-    layout = HorizontalLayoutRef(layoutChildren, 5);
+    m_layout = HorizontalLayoutRef(layoutChildren, 5);
   }
-  return layout;
+  return m_layout;
 }
 
 double LinearModel::evaluate(double * modelCoefficients, double x) const {
diff --git a/apps/regression/model/logarithmic_model.cpp b/apps/regression/model/logarithmic_model.cpp
index 5fece554d..4cec75544 100644
--- a/apps/regression/model/logarithmic_model.cpp
+++ b/apps/regression/model/logarithmic_model.cpp
@@ -8,8 +8,7 @@ using namespace Poincare;
 namespace Regression {
 
 LayoutReference LogarithmicModel::layout() {
-  static LayoutReference layout;
-  if (layout.isUninitialized()) {
+  if (m_layout.isUninitialized()) {
     const LayoutReference layoutChildren[] = {
       CharLayoutRef('a', KDText::FontSize::Small),
       CharLayoutRef(Ion::Charset::MiddleDot, KDText::FontSize::Small),
@@ -21,9 +20,9 @@ LayoutReference LogarithmicModel::layout() {
       CharLayoutRef('+', KDText::FontSize::Small),
       CharLayoutRef('b', KDText::FontSize::Small)
     };
-    layout = HorizontalLayoutRef(layoutChildren, 9);
+    m_layout = HorizontalLayoutRef(layoutChildren, 9);
   }
-  return layout;
+  return m_layout;
 }
 
 double LogarithmicModel::evaluate(double * modelCoefficients, double x) const {
diff --git a/apps/regression/model/logistic_model.cpp b/apps/regression/model/logistic_model.cpp
index e22ff63ef..76d3c0cf1 100644
--- a/apps/regression/model/logistic_model.cpp
+++ b/apps/regression/model/logistic_model.cpp
@@ -7,8 +7,7 @@ using namespace Poincare;
 namespace Regression {
 
 LayoutReference LogisticModel::layout() {
-  static LayoutReference layout;
-  if (layout.isUninitialized()) {
+  if (m_layout.isUninitialized()) {
     const LayoutReference exponentLayoutChildren[] = {
       CharLayoutRef('-', KDText::FontSize::Small),
       CharLayoutRef('b', KDText::FontSize::Small),
@@ -26,12 +25,12 @@ LayoutReference LogisticModel::layout() {
           VerticalOffsetLayoutNode::Type::Superscript
         )
     };
-    layout = FractionLayoutRef(
+    m_layout = FractionLayoutRef(
        CharLayoutRef('c', KDText::FontSize::Small),
        HorizontalLayoutRef(layoutChildren, 6)
       );
   }
-  return layout;
+  return m_layout;
 }
 
 double LogisticModel::evaluate(double * modelCoefficients, double x) const {
diff --git a/apps/regression/model/model.cpp b/apps/regression/model/model.cpp
index 129eb6083..0015e6e27 100644
--- a/apps/regression/model/model.cpp
+++ b/apps/regression/model/model.cpp
@@ -11,6 +11,10 @@ using namespace Shared;
 
 namespace Regression {
 
+void Model::tidy() {
+  m_layout = LayoutReference();
+}
+
 double Model::levelSet(double * modelCoefficients, double xMin, double step, double xMax, double y, Poincare::Context * context) {
   Expression yExpression = Decimal(y);
   PoincareHelpers::Simplify(&yExpression, *context);
diff --git a/apps/regression/model/model.h b/apps/regression/model/model.h
index fb8619d25..d9dfcde59 100644
--- a/apps/regression/model/model.h
+++ b/apps/regression/model/model.h
@@ -26,6 +26,8 @@ public:
   static constexpr int k_maxNumberOfCoefficients = 5; // This has to verify: k_maxNumberOfCoefficients < Matrix::k_maxNumberOfCoefficients
   virtual ~Model() = default;
   virtual Poincare::LayoutReference layout() = 0;
+  // Reinitialize m_layout to empty the pool
+  void tidy();
   // simplifiedExpression is overrided only by Models that override levelSet
   virtual Poincare::Expression simplifiedExpression(double * modelCoefficients, Poincare::Context * context) { return Poincare::Expression(); }
   virtual I18n::Message formulaMessage() const = 0;
@@ -37,6 +39,7 @@ public:
 protected:
   // Fit
   virtual bool dataSuitableForFit(Store * store, int series) const;
+  Poincare::LayoutReference m_layout;
 private:
   // Model attributes
   virtual double partialDerivate(double * modelCoefficients, int derivateCoefficientIndex, double x) const = 0;
diff --git a/apps/regression/model/power_model.cpp b/apps/regression/model/power_model.cpp
index 31b4ef1a6..559ad6d97 100644
--- a/apps/regression/model/power_model.cpp
+++ b/apps/regression/model/power_model.cpp
@@ -8,8 +8,7 @@ using namespace Poincare;
 namespace Regression {
 
 LayoutReference PowerModel::layout() {
-  static LayoutReference layout;
-  if (layout.isUninitialized()) {
+  if (m_layout.isUninitialized()) {
     const LayoutReference layoutChildren[] = {
       CharLayoutRef('a', KDText::FontSize::Small),
       CharLayoutRef(Ion::Charset::MiddleDot, KDText::FontSize::Small),
@@ -19,9 +18,9 @@ LayoutReference PowerModel::layout() {
           VerticalOffsetLayoutNode::Type::Superscript
         ),
       };
-    layout = HorizontalLayoutRef(layoutChildren, 4);
+    m_layout = HorizontalLayoutRef(layoutChildren, 4);
   }
-  return layout;
+  return m_layout;
 }
 
 double PowerModel::evaluate(double * modelCoefficients, double x) const {
diff --git a/apps/regression/model/quadratic_model.cpp b/apps/regression/model/quadratic_model.cpp
index d3f533ae0..03b7c73d6 100644
--- a/apps/regression/model/quadratic_model.cpp
+++ b/apps/regression/model/quadratic_model.cpp
@@ -9,8 +9,7 @@ using namespace Shared;
 namespace Regression {
 
 LayoutReference QuadraticModel::layout() {
-  static LayoutReference layout;
-  if (layout.isUninitialized()) {
+  if (m_layout.isUninitialized()) {
     const LayoutReference layoutChildren[] = {
       CharLayoutRef('a', KDText::FontSize::Small),
       CharLayoutRef(Ion::Charset::MiddleDot, KDText::FontSize::Small),
@@ -26,9 +25,9 @@ LayoutReference QuadraticModel::layout() {
       CharLayoutRef('+', KDText::FontSize::Small),
       CharLayoutRef('c', KDText::FontSize::Small),
     };
-    layout = HorizontalLayoutRef(layoutChildren, 10);
+    m_layout = HorizontalLayoutRef(layoutChildren, 10);
   }
-  return layout;
+  return m_layout;
 }
 
 Expression QuadraticModel::simplifiedExpression(double * modelCoefficients, Poincare::Context * context) {
diff --git a/apps/regression/model/quartic_model.cpp b/apps/regression/model/quartic_model.cpp
index 601f00e7a..97022fa5b 100644
--- a/apps/regression/model/quartic_model.cpp
+++ b/apps/regression/model/quartic_model.cpp
@@ -9,8 +9,7 @@ using namespace Shared;
 namespace Regression {
 
 LayoutReference QuarticModel::layout() {
-  static LayoutReference layout;
-  if (layout.isUninitialized()) {
+  if (m_layout.isUninitialized()) {
     const LayoutReference layoutChildren[] = {
       CharLayoutRef('a', KDText::FontSize::Small),
       CharLayoutRef(Ion::Charset::MiddleDot, KDText::FontSize::Small),
@@ -42,9 +41,9 @@ LayoutReference QuarticModel::layout() {
       CharLayoutRef('+', KDText::FontSize::Small),
       CharLayoutRef('e', KDText::FontSize::Small),
     };
-    layout = HorizontalLayoutRef(layoutChildren, 20);
+    m_layout = HorizontalLayoutRef(layoutChildren, 20);
   }
-  return layout;
+  return m_layout;
 }
 
 Expression QuarticModel::simplifiedExpression(double * modelCoefficients, Poincare::Context * context) {
diff --git a/apps/regression/model/trigonometric_model.cpp b/apps/regression/model/trigonometric_model.cpp
index 3b1280599..95e427a4a 100644
--- a/apps/regression/model/trigonometric_model.cpp
+++ b/apps/regression/model/trigonometric_model.cpp
@@ -10,8 +10,7 @@ using namespace Shared;
 namespace Regression {
 
 LayoutReference TrigonometricModel::layout() {
-  static LayoutReference layout;
-  if (layout.isUninitialized()) {
+  if (m_layout.isUninitialized()) {
     const LayoutReference layoutChildren[] = {
       CharLayoutRef('a', KDText::FontSize::Small),
       CharLayoutRef(Ion::Charset::MiddleDot, KDText::FontSize::Small),
@@ -28,9 +27,9 @@ LayoutReference TrigonometricModel::layout() {
       CharLayoutRef('+', KDText::FontSize::Small),
       CharLayoutRef('d', KDText::FontSize::Small)
     };
-    layout = HorizontalLayoutRef(layoutChildren, 14);
+    m_layout = HorizontalLayoutRef(layoutChildren, 14);
   }
-  return layout;
+  return m_layout;
 }
 
 Expression TrigonometricModel::simplifiedExpression(double * modelCoefficients, Poincare::Context * context) {
diff --git a/apps/regression/store.cpp b/apps/regression/store.cpp
index 61e893f74..af0ba6edd 100644
--- a/apps/regression/store.cpp
+++ b/apps/regression/store.cpp
@@ -28,6 +28,12 @@ Store::Store() :
   }
 }
 
+void Store::tidy() {
+  for (int i = 0; i < Model::k_numberOfModels; i++) {
+    regressionModel(i)->tidy();
+  }
+}
+
 /* Regressions */
 void Store::setSeriesRegressionType(int series, Model::Type type) {
   assert(series >= 0 && series < k_numberOfSeries);
diff --git a/apps/regression/store.h b/apps/regression/store.h
index 72ff6a390..81e5350bc 100644
--- a/apps/regression/store.h
+++ b/apps/regression/store.h
@@ -22,6 +22,9 @@ class Store : public Shared::InteractiveCurveViewRange, public Shared::DoublePai
 public:
   Store();
 
+  // Clean pool
+  void tidy();
+
   // Regression
   void setSeriesRegressionType(int series, Model::Type type);
   Model::Type seriesRegressionType(int series) {