diff --git a/include/scripting.h b/include/scripting.h
index e2bfb1ff..c08bbd74 100644
--- a/include/scripting.h
+++ b/include/scripting.h
@@ -30,8 +30,9 @@ class Scripting
 {
 public:
     Scripting(MainWindow *mainWindow);
-    static void stop();
+    ~Scripting();
     static void init(MainWindow *mainWindow);
+    static void stop();
     static void populateGlobalObject(MainWindow *mainWindow);
     static QJSEngine *getEngine();
     static void invokeAction(int actionIndex);
diff --git a/include/scriptutility.h b/include/scriptutility.h
index 639e71f6..0d6fca75 100644
--- a/include/scriptutility.h
+++ b/include/scriptutility.h
@@ -10,7 +10,8 @@ class ScriptUtility : public QObject
 
 public:
     ScriptUtility(MainWindow *mainWindow);
-    void clearActions();
+    ~ScriptUtility();
+
     QString getActionFunctionName(int actionIndex);
     Q_INVOKABLE bool registerAction(QString functionName, QString actionName, QString shortcut = "");
     Q_INVOKABLE bool registerToggleAction(QString functionName, QString actionName, QString shortcut = "", bool checked = false);
@@ -59,6 +60,7 @@ private:
 
     MainWindow *window;
     QList<QAction *> registeredActions;
+    QSet<QTimer *> activeTimers;
     QHash<int, QString> actionMap;
 };
 
diff --git a/include/ui/noscrollcombobox.h b/include/ui/noscrollcombobox.h
index 43db9deb..7b6f7522 100644
--- a/include/ui/noscrollcombobox.h
+++ b/include/ui/noscrollcombobox.h
@@ -14,6 +14,8 @@ public:
     void setNumberItem(int value);
     void setHexItem(uint32_t value);
     void setClearButtonEnabled(bool enabled);
+    void setEditable(bool editable);
+    void setLineEdit(QLineEdit *edit);
 
 private:
     void setItem(int index, const QString &text);
diff --git a/src/scriptapi/apiutility.cpp b/src/scriptapi/apiutility.cpp
index 61b6e978..a4aeae96 100644
--- a/src/scriptapi/apiutility.cpp
+++ b/src/scriptapi/apiutility.cpp
@@ -7,6 +7,18 @@ ScriptUtility::ScriptUtility(MainWindow *mainWindow) {
     this->window = mainWindow;
 }
 
+ScriptUtility::~ScriptUtility() {
+    if (window && window->ui && window->ui->menuTools) {
+        for (auto action : this->registeredActions) {
+            window->ui->menuTools->removeAction(action);
+        }
+    }
+    for (auto timer : this->activeTimers) {
+        timer->stop();
+        delete timer;
+    }
+}
+
 bool ScriptUtility::registerAction(QString functionName, QString actionName, QString shortcut) {
     if (!window || !window->ui || !window->ui->menuTools)
         return false;
@@ -44,12 +56,6 @@ bool ScriptUtility::registerToggleAction(QString functionName, QString actionNam
     return true;
 }
 
-void ScriptUtility::clearActions() {
-    for (auto action : this->registeredActions) {
-        window->ui->menuTools->removeAction(action);
-    }
-}
-
 QString ScriptUtility::getActionFunctionName(int actionIndex) {
     return this->actionMap.value(actionIndex);
 }
@@ -58,11 +64,15 @@ void ScriptUtility::setTimeout(QJSValue callback, int milliseconds) {
   if (!callback.isCallable() || milliseconds < 0)
       return;
 
-    QTimer *timer = new QTimer(0);
+    QTimer *timer = new QTimer();
     connect(timer, &QTimer::timeout, [=](){
-        this->callTimeoutFunction(callback);
+        if (this->activeTimers.remove(timer)) {
+            this->callTimeoutFunction(callback);
+            timer->deleteLater();
+        }
     });
-    connect(timer, &QTimer::timeout, timer, &QTimer::deleteLater);
+
+    this->activeTimers.insert(timer);
     timer->setSingleShot(true);
     timer->start(milliseconds);
 }
diff --git a/src/scriptapi/scripting.cpp b/src/scriptapi/scripting.cpp
index 82944be9..71fbabca 100644
--- a/src/scriptapi/scripting.cpp
+++ b/src/scriptapi/scripting.cpp
@@ -1,8 +1,10 @@
+#include <QQmlEngine>
+
 #include "scripting.h"
 #include "log.h"
 #include "config.h"
 
-QMap<CallbackType, QString> callbackFunctions = {
+const QMap<CallbackType, QString> callbackFunctions = {
     {OnProjectOpened, "onProjectOpened"},
     {OnProjectClosed, "onProjectClosed"},
     {OnBlockChanged, "onBlockChanged"},
@@ -22,10 +24,6 @@ QMap<CallbackType, QString> callbackFunctions = {
 Scripting *instance = nullptr;
 
 void Scripting::stop() {
-    if (!instance) return;
-    instance->engine->setInterrupted(true);
-    instance->scriptUtility->clearActions();
-    qDeleteAll(instance->imageCache);
     delete instance;
     instance = nullptr;
 }
@@ -39,7 +37,7 @@ void Scripting::init(MainWindow *mainWindow) {
 
 Scripting::Scripting(MainWindow *mainWindow) {
     this->mainWindow = mainWindow;
-    this->engine = new QJSEngine(mainWindow);
+    this->engine = new QJSEngine();
     this->engine->installExtensions(QJSEngine::ConsoleExtension);
     const QStringList paths = userConfig.getCustomScriptPaths();
     const QList<bool> enabled = userConfig.getCustomScriptsEnabled();
@@ -51,6 +49,13 @@ Scripting::Scripting(MainWindow *mainWindow) {
     this->scriptUtility = new ScriptUtility(mainWindow);
 }
 
+Scripting::~Scripting() {
+    this->engine->setInterrupted(true);
+    qDeleteAll(this->imageCache);
+    delete this->engine;
+    delete this->scriptUtility;
+}
+
 void Scripting::loadModules(QStringList moduleFiles) {
     for (QString filepath : moduleFiles) {
         QString validPath = Project::getExistingFilepath(filepath);
@@ -79,6 +84,11 @@ void Scripting::populateGlobalObject(MainWindow *mainWindow) {
     instance->engine->globalObject().setProperty("overlay", instance->engine->newQObject(mainWindow->ui->graphicsView_Map));
     instance->engine->globalObject().setProperty("utility", instance->engine->newQObject(instance->scriptUtility));
 
+    // Note: QJSEngine also has these functions, but not in Qt 5.15.
+    QQmlEngine::setObjectOwnership(mainWindow, QQmlEngine::CppOwnership);
+    QQmlEngine::setObjectOwnership(mainWindow->ui->graphicsView_Map, QQmlEngine::CppOwnership);
+    QQmlEngine::setObjectOwnership(instance->scriptUtility, QQmlEngine::CppOwnership);
+
     QJSValue constants = instance->engine->newObject();
 
     // Get version numbers
diff --git a/src/ui/noscrollcombobox.cpp b/src/ui/noscrollcombobox.cpp
index fcb662c7..5288ad97 100644
--- a/src/ui/noscrollcombobox.cpp
+++ b/src/ui/noscrollcombobox.cpp
@@ -23,6 +23,18 @@ NoScrollComboBox::NoScrollComboBox(QWidget *parent)
     this->setValidator(validator);
 }
 
+// On macOS QComboBox::setEditable and QComboBox::setLineEdit will override our changes to the focus policy, so we enforce it here.
+void NoScrollComboBox::setEditable(bool editable) {
+    auto policy = focusPolicy();
+    QComboBox::setEditable(editable);
+    setFocusPolicy(policy);
+}
+void NoScrollComboBox::setLineEdit(QLineEdit *edit) {
+    auto policy = focusPolicy();
+    QComboBox::setLineEdit(edit);
+    setFocusPolicy(policy);
+}
+
 void NoScrollComboBox::wheelEvent(QWheelEvent *event)
 {
     // Only allow scrolling to modify contents when it explicitly has focus.