not working yet

app/gcompose/src/ContextModel.cpp

@@ -148,6 +148,7 @@ QVariant ContextModel::data(const QModelIndex& index, int role) const {
     if (!index.isValid()) return QVariant();
 
     uLib::Object* obj = static_cast<uLib::Object*>(index.internalPointer());
+    if (!obj) return QVariant();
     
     if (role == Qt::DisplayRole) {
         QString typeName = getDemangledName(typeid(*obj));

app/gcompose/src/QViewportPane.cpp

@@ -94,8 +94,8 @@ void QViewportPane::setObject(uLib::Object* obj) {
 
 void QViewportPane::setViewport(QWidget* viewport, const QString& title) {
     if (m_viewport) {
-        m_viewport->parentWidget()->layout()->removeWidget(m_viewport);
-        delete m_viewport;
+        // Use deleteLater() instead of delete to avoid crashes during repaint cycles
+        m_viewport->deleteLater();
     }
     m_viewport = viewport;
     m_titleLabel->setText(title);
@@ -105,21 +105,8 @@ void QViewportPane::setViewport(QWidget* viewport, const QString& title) {
     mainAreaLayout->insertWidget(0, m_viewport);
 }
 
-
 QViewportPane::~QViewportPane() {}
 
-void QViewportPane::setViewport(QWidget* viewport, const QString& title) {
-    if (m_viewport) {
-        m_layout->removeWidget(m_viewport);
-        delete m_viewport;
-    }
-    m_viewport = viewport;
-    m_titleLabel->setText(title);
-
-    m_viewport->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
-    m_layout->addWidget(m_viewport);
-}
-
 void QViewportPane::addVtkViewport() {
     auto* viewport = new uLib::Vtk::QViewport(this);
     setViewport(viewport, "VTK Viewport");

app/gcompose/src/ViewportPane.cpp

@@ -115,7 +115,7 @@ void ViewportPane::setObject(uLib::Object* obj) {
 
 void ViewportPane::setViewport(QWidget* viewport, const QString& title) {
     if (m_viewport) {
-        delete m_viewport;
+        m_viewport->deleteLater();
     }
     m_viewport = viewport;
     m_titleLabel->setText(title);