diff --git a/src/Lib/AbstractDocument.hh b/src/Lib/AbstractDocument.hh
index 12780daa2c307d0f9c1fd32bdcd2bb56ba56e3ef..b561acfc284733abcbc49acb077152db40054867 100644
--- a/src/Lib/AbstractDocument.hh
+++ b/src/Lib/AbstractDocument.hh
@@ -16,9 +16,16 @@ class AbstractDocument : public QObject {
     Q_OBJECT
     VIVY_UNMOVABLE_OBJECT(AbstractDocument)
 
+public:
+    enum class Type : quint64 {
+        Vivy   = Utils::toUnderlying(Utils::DocumentType::Vivy),
+        Script = Utils::toUnderlying(Utils::DocumentType::VivyScript)
+    };
+
 protected:
-    AbstractDocument(const QString &documentName)
-        : name(documentName)
+    AbstractDocument(Type childType, const QString &documentName)
+        : type(childType)
+        , name(documentName)
     {
     }
 
@@ -45,6 +52,7 @@ protected:
         return false;
     }
 
+    Type type;
     QString name{};
     const Uuid uuid{};
 
@@ -52,6 +60,7 @@ public:
     virtual bool rename(const QString &) noexcept = 0;
 
     QString getName() const noexcept { return name; }
+    Type getType() const noexcept { return type; }
     Uuid getUuid() const noexcept { return uuid; }
 
 signals:
diff --git a/src/Lib/Document/CRTPSubDocument.hh b/src/Lib/Document/CRTPSubDocument.hh
index 43c7871a6423687119b6555e12f5fbad6d6141e6..eb6683d58a6b3eeddf3ed47bc1265b67791beee8 100644
--- a/src/Lib/Document/CRTPSubDocument.hh
+++ b/src/Lib/Document/CRTPSubDocument.hh
@@ -49,7 +49,6 @@ public:
     }
 
     inline Type getType() const noexcept { return fileType; }
-
     inline QString getFilePath() const noexcept { return filePath; }
 };
 
diff --git a/src/Lib/Document/VivyDocument.cc b/src/Lib/Document/VivyDocument.cc
index abced6795dc2dba14de48716defbf06ab82b8998..54c433721d31f10115ca7d3bd942adc88564e626 100644
--- a/src/Lib/Document/VivyDocument.cc
+++ b/src/Lib/Document/VivyDocument.cc
@@ -10,7 +10,7 @@
 using namespace Vivy;
 
 VivyDocument::VivyDocument(const QString &documentPath, Options opt)
-    : AbstractDocument(documentPath)
+    : AbstractDocument(AbstractDocument::Type::Vivy, documentPath)
     , documentOptions(opt)
 {
     QFileInfo file(name);
@@ -224,6 +224,7 @@ VivyDocument::getElementName() const noexcept
 {
     return getName();
 }
+
 QJsonDocument
 VivyDocument::getProperties() const noexcept
 {
diff --git a/src/Lib/Script/ScriptDocument.cc b/src/Lib/Script/ScriptDocument.cc
index 5b7c4a2701b077717e7a30508482b707b90dc6a3..2f4483e324d5ea3d03a5e8037a7d30306a89409e 100644
--- a/src/Lib/Script/ScriptDocument.cc
+++ b/src/Lib/Script/ScriptDocument.cc
@@ -5,7 +5,7 @@
 using namespace Vivy;
 
 ScriptDocument::ScriptDocument(const QString &path)
-    : AbstractDocument(path)
+    : AbstractDocument(AbstractDocument::Type::Script, path)
 {
     const QFileInfo file(path);
     if (!file.exists())
diff --git a/src/Lib/Utils.hh b/src/Lib/Utils.hh
index 20c60e04cb7ab4498c176a8c3edc101b2617cfe0..e8095145f4ed85b989f84e08ac03655115757cbf 100644
--- a/src/Lib/Utils.hh
+++ b/src/Lib/Utils.hh
@@ -62,6 +62,49 @@ const QString &getScriptFileSuffixFilter() noexcept;
 const QString &getVivyDocumentFileSuffixFilter() noexcept;
 const QString &getAnyDocumentFileSuffixFilter() noexcept;
 
+static constexpr std::size_t pointerAlignement = alignof(void *);
+
+inline std::string &
+ltrim(std::string &s, const char *t = " \t\n\r\f\v")
+{
+    s.erase(0, s.find_first_not_of(t));
+    return s;
+}
+
+inline std::string &
+rtrim(std::string &s, const char *t = " \t\n\r\f\v")
+{
+    s.erase(s.find_last_not_of(t) + 1);
+    return s;
+}
+
+inline std::string &
+trim(std::string &s, const char *t = " \t\n\r\f\v")
+{
+    return ltrim(rtrim(s, t), t);
+}
+
+template <typename T> inline void
+uniqAndSort(std::vector<T> &vec) noexcept
+{
+    std::sort(std::begin(vec), std::end(vec));
+    vec.erase(std::unique(std::begin(vec), std::end(vec)), std::end(vec));
+}
+
+// WARN: The V1 and V2 vectors need to be sorted before calling this function.
+template <typename T> inline std::vector<T>
+sortedSetDifference(const std::vector<T> &v1, const std::vector<T> &v2)
+{
+    std::vector<T> res{};
+
+    // Do V1 - V2 -> RES
+    std::set_difference(std::begin(v1), std::end(v1), // V1
+                        std::begin(v2), std::end(v2), // V2
+                        std::inserter(res, std::begin(res)));
+
+    return res;
+}
+
 enum class DocumentType : quint64 {
     /* Basic types */
     Vivy = (1 << 1),
diff --git a/src/UI/AboutWindow.cc b/src/UI/AboutWindow.cc
index fb916a803bfa4c78d420bb342a583a173cd1bbfc..90b25a0bf343da6bbe464ab2879a4cc50611f54f 100644
--- a/src/UI/AboutWindow.cc
+++ b/src/UI/AboutWindow.cc
@@ -69,9 +69,7 @@ AboutWindow::LicenceLabel::LicenceLabel(QWidget *parent, const QString &url,
     switch (format) {
     case Qt::PlainText:
     case Qt::RichText: setText(content.readAll()); break;
-
     case Qt::MarkdownText: setMarkdown(content.readAll()); break;
-
     case Qt::AutoText: qCritical() << "Invalid text format for LicenceLabel" << format;
     }
 }
diff --git a/src/UI/AbstractDocumentView.hh b/src/UI/AbstractDocumentView.hh
index 29d22aedd82fa099e04d75dd0e6e36bc7c765fca..7b1f4c807333e799fc4aa795b90fd548fc6f4eb3 100644
--- a/src/UI/AbstractDocumentView.hh
+++ b/src/UI/AbstractDocumentView.hh
@@ -25,9 +25,10 @@ public:
         Script = Utils::toUnderlying(Utils::DocumentType::VivyScript)
     };
 
-public:
+protected:
     explicit AbstractDocumentView(Type, QWidget *parent = nullptr) noexcept;
 
+public:
     virtual void closeDocument() noexcept  = 0;
     virtual void openProperties() noexcept = 0;
 
diff --git a/src/UI/DocumentViews/AssLinesModel.cc b/src/UI/DocumentViews/AssLinesModel.cc
index 58616e134ffdde48daf4af9baa09c6f56544910b..c02396a50156529b246b2c7126e18424ab52dadd 100644
--- a/src/UI/DocumentViews/AssLinesModel.cc
+++ b/src/UI/DocumentViews/AssLinesModel.cc
@@ -69,16 +69,10 @@ AssLinesModel::data(const QModelIndex &index, int role) const noexcept
     if (Qt::DisplayRole == role) {
         switch (column) {
         case Item::Field::Text: return line->getLineText();
-
-        // We want a warning when adding a field so don"t use "default"
         case Item::Field::TotalFieldCount: qFatal("Unreachable");
         }
     }
 
-    // Happily ignore the edit role for now
-    else if (Qt::EditRole == role) {
-    }
-
     return QVariant();
 }
 
diff --git a/src/VivyApplication.cc b/src/VivyApplication.cc
index b9c0dbfea0ae9086172ec5cdf0897512276dde84..f3e17144af99bdce902167f4f286bf1f7d7a1a92 100644
--- a/src/VivyApplication.cc
+++ b/src/VivyApplication.cc
@@ -57,8 +57,8 @@ VivyApplication::exec() noexcept
     setCursorFlashTime(0);
 
     // Show the main window
-    MainWindow mainWindow;
-    mainWindow.show();
+    mainWindowPtr = std::make_unique<MainWindow>();
+    mainWindowPtr->show();
 
     // Main loop
     return QApplication::exec();
@@ -67,24 +67,35 @@ VivyApplication::exec() noexcept
 QFont
 VivyApplication::getApplicationFont(Font id) const noexcept
 {
-    switch (id) {
-    case Font::Monospace:
-        return QFont(QFontDatabase::applicationFontFamilies(fontIdMonospace).at(0));
-
-    case Font::MonospaceBold:
-        return QFont(QFontDatabase::applicationFontFamilies(fontIdMonospaceBold).at(0));
-
-    case Font::DefaultItalic:
-        return QFont(QFontDatabase::applicationFontFamilies(fontIdItalic).at(0));
+    const auto getFontFromId = [](int fid) noexcept -> QFont {
+        return QFont(QFontDatabase::applicationFontFamilies(fid).at(0));
+    };
 
-    case Font::DefaultBoldItalic:
-        return QFont(QFontDatabase::applicationFontFamilies(fontIdBoldItalic).at(0));
-
-    case Font::DefaultBold: return QFont(QFontDatabase::applicationFontFamilies(fontIdBold).at(0));
-
-    case Font::Default: return QFont(QFontDatabase::applicationFontFamilies(fontIdRegular).at(0));
+    switch (id) {
+    case Font::Monospace: return getFontFromId(fontIdMonospace);
+    case Font::MonospaceBold: return getFontFromId(fontIdMonospaceBold);
+    case Font::DefaultItalic: return getFontFromId(fontIdItalic);
+    case Font::DefaultBoldItalic: return getFontFromId(fontIdBoldItalic);
+    case Font::DefaultBold: return getFontFromId(fontIdBold);
+    case Font::Default: return getFontFromId(fontIdRegular);
     }
 
     // Let the program crash
     qFatal("UNREACHABLE");
 }
+
+MainWindow *
+VivyApplication::getMainWindow() const
+{
+    if (!mainWindowPtr)
+        throw std::logic_error("No main window in the graphic VivyApplication");
+    return mainWindowPtr.get();
+}
+
+AbstractDocument *
+VivyApplication::getCurrentDocument() const
+{
+    if (!mainWindowPtr)
+        throw std::logic_error("No main window in the graphic VivyApplication");
+    return mainWindowPtr.get()->getCurrentDocument();
+}
diff --git a/src/VivyApplication.hh b/src/VivyApplication.hh
index a13719cda18f38253f0181147f9559f3ff776f34..757dcff18f8e029802675da3cff344b4147512a6 100644
--- a/src/VivyApplication.hh
+++ b/src/VivyApplication.hh
@@ -6,6 +6,9 @@
 
 #define vivyApp static_cast<VivyApplication *>(QApplication::instance())
 
+#define currentVivyDocument() dynamic_cast<VivyDocument*>(vivyApp->getCurrentDocument())
+#define currentScriptDocument dynamic_cast<ScriptDocument*>(vivyApp->getCurrentDocument())
+
 // Only support dark theme for now
 #define VIVY_ICON_APP     ":icons/vivy.png"
 #define VIVY_ICON_SCRIPT  ":icons/lua.png"
@@ -33,6 +36,9 @@
 
 namespace Vivy
 {
+class MainWindow;
+
+// Vivy application class
 class VivyApplication : public QApplication {
     Q_OBJECT
 
@@ -46,14 +52,10 @@ public:
         Default,
         DefaultItalic,
         DefaultBold,
-        DefaultBoldItalic,
+        DefaultBoldItalic
     };
 
-    enum class Theme {
-        System,
-        Dark,
-        Light,
-    };
+    enum class Theme { System, Dark, Light };
 
 private:
     int fontIdMonospace;
@@ -63,12 +65,16 @@ private:
     int fontIdBold;
     int fontIdBoldItalic;
 
+    std::unique_ptr<MainWindow> mainWindowPtr{ nullptr };
+
 public:
     VivyApplication(int &argc, char **argv);
 
     int exec() noexcept;
 
     QFont getApplicationFont(Font) const noexcept;
+    [[nodiscard("handle-it")]] MainWindow *getMainWindow() const;
+    [[nodiscard("handle-it")]] AbstractDocument *getCurrentDocument() const;
     void setTheme(Theme) noexcept;
 };