diff --git a/src/core/settings.cpp b/src/core/settings.cpp
index 5164a8a7..61f471ed 100644
--- a/src/core/settings.cpp
+++ b/src/core/settings.cpp
@@ -64,6 +64,8 @@ void Settings::load()
 
     QString key = QString::fromLatin1(KEY) + QLatin1String("/General/");
 
+    appVersion = settings->value(key + QLatin1String("AppVersion"), APP_VERSION_UNKN).toString().toUInt(0, 16);
+
     // Angle mode special case.
     QString angleUnitStr;
     angleUnitStr = settings->value(key + QLatin1String("AngleMode"), "r").toString();
@@ -224,6 +226,8 @@ void Settings::save()
     int k, i;
     QString key = KEY + QLatin1String("/General/");
 
+    settings->setValue(key + QLatin1String("AppVersion"), QString().sprintf("0x%06X", APP_VERSION));
+
     settings->setValue(key + QLatin1String("HistorySave"), historySave);
     settings->setValue(key + QLatin1String("LeaveLastExpression"), leaveLastExpression);
     settings->setValue(key + QLatin1String("VariableSave"), variableSave);
diff --git a/src/core/settings.h b/src/core/settings.h
index 3de94172..8fa3cd9f 100644
--- a/src/core/settings.h
+++ b/src/core/settings.h
@@ -26,6 +26,13 @@
 #include <QtCore/QStringList>
 #include <QtCore/QList>
 
+// current application version (0xMMNNPP format same as QT_VERSION) 
+#define APP_VERSION 0x001200
+// milestones for compatibility checks
+#define APP_VERSION_001200 0x001200
+// unknown format (always <APP_VERSION) 
+#define APP_VERSION_UNKN 0x000000
+
 class Settings {
 public:
     static Settings* instance();
@@ -33,6 +40,8 @@ class Settings {
     void load();
     void save();
 
+    unsigned appVersion; // 0xMMNNPP format
+
     char radixCharacter() const; // 0: Automatic.
     void setRadixCharacter(char c = 0);
     bool isRadixCharacterAuto() const;
diff --git a/src/gui/mainwindow.cpp b/src/gui/mainwindow.cpp
index 48b32330..a7458c77 100644
--- a/src/gui/mainwindow.cpp
+++ b/src/gui/mainwindow.cpp
@@ -93,6 +93,13 @@ QTranslator* MainWindow::createTranslator(const QString& langCode)
 
 void MainWindow::createUi()
 {
+    // set docking behavior
+    setCorner(Qt::TopLeftCorner, Qt::LeftDockWidgetArea);
+    setCorner(Qt::BottomLeftCorner, Qt::LeftDockWidgetArea);
+    setCorner(Qt::TopRightCorner, Qt::RightDockWidgetArea);
+    setCorner(Qt::BottomRightCorner, Qt::RightDockWidgetArea);
+    setDockNestingEnabled(true);
+  
     createActions();
     createActionGroups();
     createActionShortcuts();
@@ -1002,6 +1009,10 @@ void MainWindow::applySettings()
     } else
         move(m_settings->windowPosition);
 
+    // docking layout has changed in 0.12 - reset window state
+    if (m_settings->appVersion < APP_VERSION_001200)
+      m_settings->windowState.clear();
+    
     restoreState(m_settings->windowState);
 
     m_actions.viewFullScreenMode->setChecked(m_settings->windowOnfullScreen);