diff --git a/apps/statistics/multiple_data_view.cpp b/apps/statistics/multiple_data_view.cpp
index 2f0203ca9..8e6def2fd 100644
--- a/apps/statistics/multiple_data_view.cpp
+++ b/apps/statistics/multiple_data_view.cpp
@@ -72,7 +72,7 @@ void MultipleDataView::layoutDataSubviews() {
   int numberDataSubviews = m_store->numberOfNonEmptySeries();
   assert(numberDataSubviews > 0);
   KDCoordinate bannerHeight = bannerFrame().height();
-  KDCoordinate subviewHeight = (bounds().height() - bannerHeight)/numberDataSubviews;
+  KDCoordinate subviewHeight = (bounds().height() - bannerHeight)/numberDataSubviews + 1; // +1 to make sure that all pixel rows are drawn
   int displayedSubviewIndex = 0;
   for (int i = 0; i < Store::k_numberOfSeries; i++) {
     if (!m_store->seriesIsEmpty(i)) {
diff --git a/build/toolchain.emscripten.mak b/build/toolchain.emscripten.mak
index 72d1031f5..313209791 100644
--- a/build/toolchain.emscripten.mak
+++ b/build/toolchain.emscripten.mak
@@ -65,7 +65,7 @@ _do_load_from_lexer \
 _fun_bc_call \
 _fun_builtin_var_call \
 _main \
-_micropython_port_should_interrupt \
+_micropython_port_vm_hook_loop \
 _mp_builtin___import__ \
 _mp_builtin_input \
 _mp_call_function_0 \
diff --git a/ion/src/emscripten/events_keyboard.cpp b/ion/src/emscripten/events_keyboard.cpp
index fa19c3191..ce1dcc0b6 100644
--- a/ion/src/emscripten/events_keyboard.cpp
+++ b/ion/src/emscripten/events_keyboard.cpp
@@ -83,6 +83,13 @@ Ion::Keyboard::State Ion::Keyboard::scan() {
    * function setTimeout, which can be called with a value of zero. Doing so
    * puts the callback at the end of the queue of callbacks to be processed. */
   emscripten_sleep(0);
+
+  /* Grab this opporunity to refresh the display. In practice, this routine is
+   * called from micropython_port_vm_hook_loop once in a while, so this gives us
+   * an opportunity to refresh the display during the execution of a
+   * long-running Python script. */
+  Ion::Display::Emscripten::refresh();
+
   return sKeyboardState;
 }
 
diff --git a/poincare/include/poincare/char_layout.h b/poincare/include/poincare/char_layout.h
index f06808ded..874f9a720 100644
--- a/poincare/include/poincare/char_layout.h
+++ b/poincare/include/poincare/char_layout.h
@@ -17,6 +17,7 @@ public:
 
   // CharLayout
   virtual void setChar(char c) { m_char = c; }
+  char character() const { return m_char; }
   const KDFont * font() const { return m_font; }
   void setFont(const KDFont * font) { m_font = font; }
 
@@ -24,6 +25,7 @@ public:
   void moveCursorLeft(LayoutCursor * cursor, bool * shouldRecomputeLayout) override;
   void moveCursorRight(LayoutCursor * cursor, bool * shouldRecomputeLayout) override;
   int serialize(char * buffer, int bufferSize, Preferences::PrintFloatMode floatDisplayMode, int numberOfSignificantDigits) const override;
+  bool isChar() const override { return true; }
   bool isCollapsable(int * numberOfOpenParenthesis, bool goingLeft) const override;
 
   // TreeNode
@@ -55,8 +57,10 @@ private:
 
 class CharLayout final : public Layout {
 public:
+  CharLayout(const CharLayoutNode * n) : Layout(n) {}
   CharLayout(char c, const KDFont * font = KDFont::LargeFont);
   const KDFont * font() const { return const_cast<CharLayout *>(this)->node()->font(); }
+  char character() const {return const_cast<CharLayout *>(this)->node()->character();}
 private:
   using Layout::node;
   CharLayoutNode * node() { return static_cast<CharLayoutNode *>(Layout::node());}
diff --git a/poincare/include/poincare/layout.h b/poincare/include/poincare/layout.h
index c8f2c6554..acad70aba 100644
--- a/poincare/include/poincare/layout.h
+++ b/poincare/include/poincare/layout.h
@@ -45,6 +45,7 @@ public:
   bool isMatrix() const { return const_cast<Layout *>(this)->node()->isMatrix(); }
   bool isVerticalOffset() const { return const_cast<Layout *>(this)->node()->isVerticalOffset(); }
   bool isLeftParenthesis() const { return const_cast<Layout *>(this)->node()->isLeftParenthesis(); }
+  bool isChar() const { return const_cast<Layout *>(this)->node()->isChar(); }
   bool isCollapsable(int * numberOfOpenParenthesis, bool goingLeft) const { return const_cast<Layout *>(this)->node()->isCollapsable(numberOfOpenParenthesis, goingLeft); }
   int leftCollapsingAbsorbingChildIndex() const { return const_cast<Layout *>(this)->node()->leftCollapsingAbsorbingChildIndex(); }
   int rightCollapsingAbsorbingChildIndex() const { return const_cast<Layout *>(this)->node()->rightCollapsingAbsorbingChildIndex(); }
diff --git a/poincare/include/poincare/layout_node.h b/poincare/include/poincare/layout_node.h
index c474c1c59..f9aa51d50 100644
--- a/poincare/include/poincare/layout_node.h
+++ b/poincare/include/poincare/layout_node.h
@@ -103,6 +103,7 @@ public:
   virtual bool isRightBracket() const { return false; }
   virtual bool isEmpty() const { return false; }
   virtual bool isMatrix() const { return false; }
+  virtual bool isChar() const { return false; }
   virtual bool hasUpperLeftIndex() const { return false; }
   virtual char XNTChar() const {
     LayoutNode * p = parent();
diff --git a/poincare/src/char_layout.cpp b/poincare/src/char_layout.cpp
index c4813bbae..6f3431924 100644
--- a/poincare/src/char_layout.cpp
+++ b/poincare/src/char_layout.cpp
@@ -32,17 +32,35 @@ int CharLayoutNode::serialize(char * buffer, int bufferSize, Preferences::PrintF
 }
 
 bool CharLayoutNode::isCollapsable(int * numberOfOpenParenthesis, bool goingLeft) const {
-  if (*numberOfOpenParenthesis <= 0
-      && (m_char == '+'
-        || m_char == '-'
+  if (*numberOfOpenParenthesis <= 0) {
+    if (m_char == '+'
         || m_char == '*'
         || m_char == Ion::Charset::MultiplicationSign
         || m_char == Ion::Charset::MiddleDot
         || m_char == Ion::Charset::Sto
         || m_char == '='
-        || m_char == ','))
-  {
-    return false;
+        || m_char == ',')
+    {
+      return false;
+    }
+    if (m_char == '-') {
+      /* If the expression is like 3E-200, we want '-' to be collapsable.
+       * Otherwise, '-' is not collapsable. */
+      Layout thisRef = CharLayout(this);
+      Layout parent = thisRef.parent();
+      if (!parent.isUninitialized()) {
+        int indexOfThis = parent.indexOfChild(thisRef);
+        if (indexOfThis > 0) {
+          Layout leftBrother = parent.childAtIndex(indexOfThis-1);
+          if (leftBrother.isChar()
+              && static_cast<CharLayout&>(leftBrother).character() == Ion::Charset::Exponent)
+          {
+            return true;
+          }
+        }
+      }
+      return false;
+    }
   }
   return true;
 }
diff --git a/python/port/helpers.cpp b/python/port/helpers.cpp
index 5da28c6a5..f49c06e3d 100644
--- a/python/port/helpers.cpp
+++ b/python/port/helpers.cpp
@@ -4,17 +4,28 @@ extern "C" {
 #include "mphalport.h"
 }
 
-bool micropython_port_should_interrupt() {
+void micropython_port_vm_hook_loop() {
+  /* This function is called very frequently by the MicroPython engine. We grab
+   * this opportunity to interrupt execution and/or refresh the display on
+   * platforms that need it. */
+
+  /* Doing too many things here slows down Python execution quite a lot. So we
+   * only do things once in a while and return as soon as possible otherwise. */
   static int c = 0;
-  c++;
-  if (c%20000 != 0) {
-    return false;
+
+  c = (c + 1) % 20000;
+  if (c != 0) {
+    return;
   }
-  c = 0;
-  Ion::Keyboard::State scan = Ion::Keyboard::scan();
-  if (scan.keyDown((Ion::Keyboard::Key)mp_interrupt_char)) {
+
+  /* Check if the user asked for an interruption from the keyboard */
+  if (micropython_port_should_interrupt()) {
     mp_keyboard_interrupt();
-    return true;
   }
-  return false;
+}
+
+bool micropython_port_should_interrupt() {
+  Ion::Keyboard::State scan = Ion::Keyboard::scan();
+  Ion::Keyboard::Key interruptKey = static_cast<Ion::Keyboard::Key>(mp_interrupt_char);
+  return scan.keyDown(interruptKey);
 }
diff --git a/python/port/helpers.h b/python/port/helpers.h
index 76abbde0d..73ed4c3b4 100644
--- a/python/port/helpers.h
+++ b/python/port/helpers.h
@@ -6,8 +6,7 @@ extern "C" {
 #endif
 #include <stdbool.h>
 
-/* should_interrupt effectively does something once every 20000 calls. It checks
- * if a key is down to raise an interruption flag. */
+void micropython_port_vm_hook_loop();
 bool micropython_port_should_interrupt();
 
 #ifdef __cplusplus
diff --git a/python/port/mpconfigport.h b/python/port/mpconfigport.h
index ff7fff87d..3ab2ab9b3 100644
--- a/python/port/mpconfigport.h
+++ b/python/port/mpconfigport.h
@@ -90,7 +90,7 @@
 // (This scheme won't work if we want to mix Thumb and normal ARM code.)
 #define MICROPY_MAKE_POINTER_CALLABLE(p) (p)
 
-#define MICROPY_VM_HOOK_LOOP micropython_port_should_interrupt();
+#define MICROPY_VM_HOOK_LOOP micropython_port_vm_hook_loop();
 
 typedef intptr_t mp_int_t; // must be pointer size
 typedef uintptr_t mp_uint_t; // must be pointer size