diff --git a/DicomScanService.cpp b/DicomScanService.cpp
index 3cd7f03..2969f50 100644
--- a/DicomScanService.cpp
+++ b/DicomScanService.cpp
@@ -377,12 +377,13 @@ void DicomScanService::parse(QString p_loadDir){
     s.SetComputeZSpacing( true );
     s.SetZSpacingTolerance( 1e-2 );
     
-    if(result==NOERRORS)
-        if(!s.Sort( patientInfos->filenames ) ) {
-            result=PARSER_CT_FAILED_SORTING;
+    if (result == NOERRORS) {
+        if (!s.Sort(patientInfos->filenames)) {
+            result = PARSER_CT_FAILED_SORTING;
         } else {
-            s.GetFilenames().size() == 0 ? result = PARSER_CT_FILES_MISSING : result=NOERRORS;
+            s.GetFilenames().size() == 0 ? result = PARSER_CT_FILES_MISSING : result = NOERRORS;
         }
+    }
     
     if(result == NOERRORS){
 		patientInfos->CTfiles=s.GetFilenames ();
diff --git a/LocalizationService.cpp b/LocalizationService.cpp
index ed60d67..689cd38 100644
--- a/LocalizationService.cpp
+++ b/LocalizationService.cpp
@@ -216,14 +216,14 @@ MarkerList LocalizationService::localize(
         bool ok = true;
 
         // 0: bounding-box diagonal length
-        if (params.selectedFilters.size() > 0 && params.selectedFilters[0])
+        if (params.selectedFilters[0])
         {
             if (len < params.thrDown_D || len > params.thrUp_D)
                 ok = false;
         }
 
         // 1: Hausdorff
-        if (ok && params.selectedFilters.size() > 1 && params.selectedFilters[1])
+        if (ok && params.selectedFilters[1])
         {
             double center[3];
             out->GetCenter(center);
@@ -233,7 +233,7 @@ MarkerList LocalizationService::localize(
         }
 
         // 2: side-difference
-        if (ok && params.selectedFilters.size() > 2 && params.selectedFilters[2])
+        if (ok && params.selectedFilters[2])
         {
             const double metric = sideDifferenceMetric(b);
             if (metric > params.thr_S)
diff --git a/main.cpp b/main.cpp
index 2a6a347..c19c148 100644
--- a/main.cpp
+++ b/main.cpp
@@ -38,7 +38,7 @@ int main(int argc, char **argv) {
 		msgBox.setInformativeText("Please add config.ini file in the gLocalize path.");
 		msgBox.setStandardButtons(QMessageBox::Ok);
 		msgBox.setDefaultButton(QMessageBox::Ok);
-		int ret = msgBox.exec();
+			(void)msgBox.exec();
 		cout<<"prequit" <<endl;
 		app.quit();;
 		return -1;
@@ -66,7 +66,7 @@ int main(int argc, char **argv) {
 		QGridLayout* layout = (QGridLayout*) msgBox.layout();
 		layout->addItem(horizonatlSpacer, layout->rowCount(), 0 ,1 ,layout->columnCount());
 		
-		int ret = msgBox.exec();
+			(void)msgBox.exec();
 		cout<<"prequit" <<endl;
 		app.quit();
 		delete config;
@@ -94,11 +94,11 @@ int main(int argc, char **argv) {
 	MainWindow* mainW= new MainWindow(loadPath);
     std::cout<< "pre show" <<std::endl;
     mainW->show();
-    int res= app.exec();
+	    return app.exec();
 
 
 
 
 
-    return 0;
+	    // unreachable
 }
diff --git a/mainw.cpp b/mainw.cpp
index aa07259..932dc66 100644
--- a/mainw.cpp
+++ b/mainw.cpp
@@ -15,7 +15,8 @@
 
 
 void MainWindow::onSkullMaskingUpdt(QString msg, double val){
-    Ui->progBar->setValue(val*100);
+    // SkullRemovalWorker already emits progress in percent [0..100]
+    Ui->progBar->setValue(static_cast<int>(val));
     QMetaObject::invokeMethod(Ui->statusbar, "showMessage", Qt::QueuedConnection,
                               Q_ARG(QString, msg ),
                               Q_ARG(int, 0));
@@ -124,7 +125,7 @@ MainWindow::MainWindow(QString p_loadPath){
     skull_thread= new QThread;
     skullRemoval->moveToThread(skull_thread);
     skull_thread->start();
-    connect(skullRemoval, SIGNAL(skull_mask_end(vtkImageData *)),Visualizer,SLOT(onAutoSkullMaskEnd(vtkImageData* )));
+    // Handle result in MainWindow and forward to the renderer from the GUI thread.
     connect(skullRemoval, SIGNAL(skull_mask_end(vtkImageData *)),this,SLOT(onAutoSkullMaskEnd(vtkImageData* )));
 
     connect(skullRemoval, SIGNAL(errMsg(QString)),this,SLOT(onAutoMaskError(QString )));
@@ -221,6 +222,11 @@ MainWindow::~MainWindow(){
 }
 
 void MainWindow::onAutoSkullMaskEnd(vtkImageData* img){
+    // Apply the masked volume to the renderer. gRen deep-copies the input,
+    // so we can safely free the temporary VTK image afterwards.
+    if (img && Visualizer)
+        Visualizer->onAutoSkullMaskEnd(img);
+
     QMetaObject::invokeMethod(Ui->statusbar, "showMessage", Qt::QueuedConnection,
                               Q_ARG(QString, QString("Masking Done") ),
                               Q_ARG(int, 3000));
@@ -233,6 +239,9 @@ void MainWindow::onAutoSkullMaskEnd(vtkImageData* img){
     Ui->frame_3->setEnabled(true);
     Ui->frame_4->setEnabled(true);
 
+    if (img)
+        img->Delete();
+
     return;
 }
 
diff --git a/types.h b/types.h
index 2c29505..a8f5343 100644
--- a/types.h
+++ b/types.h
@@ -1,5 +1,6 @@
 #pragma once
 
+#include <array>
 #include <vector>
 
 // Shared data model used across logic, Qt UI, and VTK rendering.
@@ -33,5 +34,5 @@ struct LocalizationParams
     //  0: bounding-box diagonal length filter
     //  1: Hausdorff distance filter
     //  2: side-difference filter
-    std::vector<bool> selectedFilters{true, true, true};
+    std::array<bool, 3> selectedFilters{true, true, true};
 };
diff --git a/ui_mainw.cpp b/ui_mainw.cpp
index 2d14383..d15251c 100644
--- a/ui_mainw.cpp
+++ b/ui_mainw.cpp
@@ -61,10 +61,14 @@ void Ui_MainWindow::setupUi(QMainWindow *MainWindow)
     frame_2->setObjectName(QString::fromUtf8("frame_2"));
     frame_2->setFrameShape(QFrame::StyledPanel);
     frame_2->setFrameShadow(QFrame::Raised);
+    // Top-level layout for frame_2 (the only layout installed on the widget)
     auto verticalLayout_2 = new QVBoxLayout(frame_2);
     verticalLayout_2->setObjectName(QString::fromUtf8("verticalLayout_2"));
-    auto formLayout_2 = new QFormLayout(frame_2);
+    // Sub-layouts must NOT be constructed with a QWidget parent, otherwise Qt tries to
+    // install them as the widget's layout and warns if the widget already has one.
+    auto formLayout_2 = new QFormLayout();
     formLayout_2->setObjectName(QString::fromUtf8("formLayout_2"));
+    verticalLayout_2->addLayout(formLayout_2);
     label_6 = new QLabel(frame_2);
     label_6->setObjectName(QString::fromUtf8("label_6"));
 
@@ -111,9 +115,6 @@ void Ui_MainWindow::setupUi(QMainWindow *MainWindow)
     l_isoV->setMinimumSize(QSize(91, 0));
     formLayout_2->setWidget(6, QFormLayout::FieldRole, l_isoV);
 
-    verticalLayout_2->addLayout(formLayout_2);
-
-
     verticalLayout_5->addWidget(frame_2);
 
     auto frame_5 = new QFrame(widget);
@@ -122,7 +123,7 @@ void Ui_MainWindow::setupUi(QMainWindow *MainWindow)
     frame_5->setFrameShadow(QFrame::Raised);
     auto verticalLayout_4 = new QVBoxLayout(frame_5);
     verticalLayout_4->setObjectName(QString::fromUtf8("verticalLayout_4"));
-    auto horizontalLayout_7 = new QHBoxLayout(frame_5);
+    auto horizontalLayout_7 = new QHBoxLayout();
     horizontalLayout_7->setObjectName(QString::fromUtf8("horizontalLayout_7"));
     label_7 = new QLabel(frame_5);
     label_7->setObjectName(QString::fromUtf8("label_7"));
@@ -139,7 +140,7 @@ void Ui_MainWindow::setupUi(QMainWindow *MainWindow)
     verticalLayout_4->addLayout(horizontalLayout_7);
 
 
-    auto manualMask_lay = new QHBoxLayout(frame_5);
+    auto manualMask_lay = new QHBoxLayout();
     manualMask_lay->setObjectName(QString::fromUtf8("manualMask_lay"));
     QLabel* l_manualMask = new QLabel(frame_5);
     l_manualMask->setObjectName(QString::fromUtf8("l_manualMask"));
@@ -166,7 +167,7 @@ void Ui_MainWindow::setupUi(QMainWindow *MainWindow)
     frame_3->setFrameShadow(QFrame::Raised);
     auto verticalLayout = new QVBoxLayout(frame_3);
     verticalLayout->setObjectName(QString::fromUtf8("verticalLayout"));
-    auto horizontalLayout = new QHBoxLayout(frame_3);
+    auto horizontalLayout = new QHBoxLayout();
     horizontalLayout->setObjectName(QString::fromUtf8("horizontalLayout"));
     label = new QLabel(frame_3);
     label->setObjectName(QString::fromUtf8("label"));
@@ -190,7 +191,7 @@ void Ui_MainWindow::setupUi(QMainWindow *MainWindow)
 
     verticalLayout->addLayout(horizontalLayout);
 
-    auto horizontalLayout_2 = new QHBoxLayout(frame_3);
+    auto horizontalLayout_2 = new QHBoxLayout();
     horizontalLayout_2->setObjectName(QString::fromUtf8("horizontalLayout_2"));
     checkBox_2 = new QCheckBox(frame_3);
     checkBox_2->setObjectName(QString::fromUtf8("checkBox_2"));
@@ -225,7 +226,7 @@ void Ui_MainWindow::setupUi(QMainWindow *MainWindow)
 
     verticalLayout->addLayout(horizontalLayout_2);
 
-    auto horizontalLayout_3 = new QHBoxLayout(frame_3);
+    auto horizontalLayout_3 = new QHBoxLayout();
     horizontalLayout_3->setObjectName(QString::fromUtf8("horizontalLayout_3"));
     checkBox_3 = new QCheckBox(frame_3);
     checkBox_3->setObjectName(QString::fromUtf8("checkBox_3"));
@@ -254,7 +255,7 @@ void Ui_MainWindow::setupUi(QMainWindow *MainWindow)
 
     verticalLayout->addLayout(horizontalLayout_3);
 
-    auto horizontalLayout_5 = new QHBoxLayout(frame_3);
+    auto horizontalLayout_5 = new QHBoxLayout();
     horizontalLayout_5->setObjectName(QString::fromUtf8("horizontalLayout_5"));
     checkBox_5 = new QCheckBox(frame_3);
     checkBox_5->setObjectName(QString::fromUtf8("checkBox_5"));
@@ -281,7 +282,7 @@ void Ui_MainWindow::setupUi(QMainWindow *MainWindow)
 
     verticalLayout->addLayout(horizontalLayout_5);
 
-    auto horizontalLayout_6 = new QHBoxLayout(frame_3);
+    auto horizontalLayout_6 = new QHBoxLayout();
     horizontalLayout_6->setObjectName(QString::fromUtf8("horizontalLayout_6"));
     pushButton_3 = new QPushButton(frame_3);
     pushButton_3->setObjectName(QString::fromUtf8("pushButton_3"));
@@ -327,7 +328,7 @@ void Ui_MainWindow::setupUi(QMainWindow *MainWindow)
 
     verticalLayout_3->addWidget(treeView);
 
-    auto formLayout = new QHBoxLayout(frame_4);
+    auto formLayout = new QHBoxLayout();
     formLayout->setObjectName(QString::fromUtf8("formLayout"));
     pushButton = new QPushButton(frame_4);
     pushButton->setObjectName(QString::fromUtf8("pushButton"));