diff --git a/agui2/src/Graphics/Connection/InputConnectionBox.cpp b/agui2/src/Graphics/Connection/InputConnectionBox.cpp
index d6a07caccc8e9a566a57252adbd1c322230f1cd9..8484d8b4f46f4de1de6d435d9329e653ccb902f2 100644
--- a/agui2/src/Graphics/Connection/InputConnectionBox.cpp
+++ b/agui2/src/Graphics/Connection/InputConnectionBox.cpp
@@ -6,7 +6,7 @@ InputConnectionBox::InputConnectionBox(GraphicsBox* parent, size_t slot)
 {}
 
 void InputConnectionBox::setConnection(Connection* connection) {
-    Q_ASSERT(!this->connection);
+    Q_ASSERT((this->connection == nullptr) != (connection == nullptr));
     this->connection = connection;
 }
 
diff --git a/agui2/src/MainWindow.cpp b/agui2/src/MainWindow.cpp
index 3897d6c69c1490af913a444750771258c56f6772..723d9239a9d5521174c0e24f656fe6dc2769a384 100644
--- a/agui2/src/MainWindow.cpp
+++ b/agui2/src/MainWindow.cpp
@@ -59,7 +59,7 @@ void MainWindow::on_RunBtn_clicked()
     try {
 #if 0
         ModelBox::clearCachedResults();
-        result = this->outputBox->getModelBox()->run();
+        result = this->outputBox->getModelBox()->evaluate();
 #else
         result = ParallelExecutor::execute(dynamic_cast<OutputModelBox*>(this->outputBox->getModelBox()));
 #endif
diff --git a/agui2/src/Models/OutputModelBox.cpp b/agui2/src/Models/OutputModelBox.cpp
index 13c2e21fc9f4e2404f5c8207b749e4c8720dad36..2181fe2c92ba02310e7f3d0ac61be4759372e765 100644
--- a/agui2/src/Models/OutputModelBox.cpp
+++ b/agui2/src/Models/OutputModelBox.cpp
@@ -10,7 +10,8 @@ std::shared_ptr<abstraction::OperationAbstraction> OutputModelBox::evaluate() {
     assert(this->inputs.size() == 1);
     if (!this->inputs[0])
         return nullptr;
-    return inputs[0]->getCachedResultOrEvaluate();
+    this->result = inputs[0]->getCachedResultOrEvaluate();
+    return this->result;
 }
 
 std::string OutputModelBox::getName() const {