diff --git a/ChangeLog.txt b/ChangeLog.txt
index 37187a83a..0ac01274f 100644
--- a/ChangeLog.txt
+++ b/ChangeLog.txt
@@ -1,4 +1,5 @@
 # Version 0.4.2
+- [#439] Widen Formula Dialog.
 - Fixed broken tool dialogs "Intersection arcs" and "Point from arc and tangent".
 - [#442] 'Broken Formula' error when using Intersect Circles tool.
 
diff --git a/src/libs/vtools/dialogs/support/dialogeditwrongformula.cpp b/src/libs/vtools/dialogs/support/dialogeditwrongformula.cpp
index 037eb2227..a523aee33 100644
--- a/src/libs/vtools/dialogs/support/dialogeditwrongformula.cpp
+++ b/src/libs/vtools/dialogs/support/dialogeditwrongformula.cpp
@@ -307,6 +307,19 @@ void DialogEditWrongFormula::closeEvent(QCloseEvent *event)
     DialogTool::closeEvent(event);
 }
 
+//---------------------------------------------------------------------------------------------------------------------
+void DialogEditWrongFormula::showEvent(QShowEvent *event)
+{
+    DialogTool::showEvent( event );
+    if ( event->spontaneous() )
+    {
+        return;
+    }
+
+    setMaximumSize(QSize(QWIDGETSIZE_MAX, QWIDGETSIZE_MAX));
+    setMinimumSize(QSize(0, 0));
+}
+
 //---------------------------------------------------------------------------------------------------------------------
 void DialogEditWrongFormula::SetFormula(const QString &value)
 {
diff --git a/src/libs/vtools/dialogs/support/dialogeditwrongformula.h b/src/libs/vtools/dialogs/support/dialogeditwrongformula.h
index 5b64662a5..e127223d7 100644
--- a/src/libs/vtools/dialogs/support/dialogeditwrongformula.h
+++ b/src/libs/vtools/dialogs/support/dialogeditwrongformula.h
@@ -79,6 +79,7 @@ public slots:
 protected:
     virtual void CheckState() Q_DECL_OVERRIDE;
     virtual void closeEvent(QCloseEvent *event) Q_DECL_OVERRIDE;
+    virtual void showEvent( QShowEvent *event ) Q_DECL_OVERRIDE;
 private:
     Q_DISABLE_COPY(DialogEditWrongFormula)
     Ui::DialogEditWrongFormula *ui;