diff --git a/colorpicker.cpp b/colorpicker.cpp
index 4140850..daf6113 100755
--- a/colorpicker.cpp
+++ b/colorpicker.cpp
@@ -261,6 +261,12 @@ void
 ColorpickerPrivate::init()
 {
     mac::setDarkAppearance();
+    // icc profile
+    ICCTransform* transform = ICCTransform::instance();
+    QDir resources(QApplication::applicationDirPath() + "/../Resources");
+    QString inputProfile = resources.filePath("sRGB2014.icc"); // built-in Qt input profile
+    transform->setInputProfile(inputProfile);
+    profile();
     // ui
     ui.reset(new Ui_Colorpicker());
     ui->setupUi(window);
@@ -382,12 +388,8 @@ ColorpickerPrivate::init()
     connect(this, &ColorpickerPrivate::readOnly, ui->s, &Label::setReadOnly);
     connect(this, &ColorpickerPrivate::readOnly, ui->v, &Label::setReadOnly);
     size = window->size();
-    // icc profile
-    ICCTransform* transform = ICCTransform::instance();
-    QDir resources(QApplication::applicationDirPath() + "/../Resources");
-    QString inputProfile = resources.filePath("sRGB2014.icc"); // built-in Qt input profile
-    transform->setInputProfile(inputProfile);
-    profile();
+    // stylesheet
+    stylesheet();
     // debug
     #ifdef QT_DEBUG
         QMenu* menu = ui->menubar->addMenu("Debug");
@@ -472,7 +474,6 @@ ColorpickerPrivate::grabBuffer(QRect rect)
     }
     QImage buffer;
     const QBrush blackBrush = QBrush(Qt::black);
-    QScreen* screen = QGuiApplication::screenAt(rect.center());
     buffer = mac::grabImage(x, y, w, h, id);
    
     QRegion geom(x, y, w, h);
@@ -656,8 +657,8 @@ ColorpickerPrivate::widget()
                     QColor color = dragcolor;
                     // icc profile
                     ICCTransform* transform = ICCTransform::instance();
-                    if (state.iccProfile != transform->outputProfile()) {
-                        color = transform->transformTo(color.rgb(), iccProfile, transform->outputProfile());
+                    if (iccCurrentProfile != transform->outputProfile()) {
+                        color = transform->transformTo(color.rgb(), iccCurrentProfile, transform->outputProfile());
                     }
                     colors.push_back(QPair<QColor,QString>(color.rgb(), QFileInfo(iccCurrentProfile).baseName()));
                 }
@@ -708,7 +709,6 @@ ColorpickerPrivate::profile()
     // icc profile
     ICCTransform* transform = ICCTransform::instance();
     transform->setOutputProfile(outputProfile);
-    stylesheet();
 }
 
 void
@@ -759,6 +759,7 @@ ColorpickerPrivate::eventFilter(QObject* object, QEvent* event)
 {
     if (event->type() == QEvent::ScreenChangeInternal) {
         profile();
+        stylesheet();
         if (active) {
             view();
             widget();
@@ -932,7 +933,6 @@ ColorpickerPrivate::drag()
     if (rect.width() > 5 && rect.height() > 5) // cluster limit
     {
         int width = image.width();
-        int height = image.height();
         int colornum = 6;
         {
             cv::utils::logging::setLogLevel(cv::utils::logging::LOG_LEVEL_SILENT);
diff --git a/colorpicker.mm b/colorpicker.mm
index a1ffdf4..df254c6 100755
--- a/colorpicker.mm
+++ b/colorpicker.mm
@@ -15,7 +15,6 @@
 {
     static QMutex mutex;
     static QPoint lastpos;
-    NSApplication* app = [NSApplication sharedApplication];
     [[NSNotificationCenter defaultCenter] addObserverForName:NSApplicationDidBecomeActiveNotification
                                                       object:nil
                                                        queue:nil
diff --git a/colorwheel.cpp b/colorwheel.cpp
index 183f46d..aed70c1 100755
--- a/colorwheel.cpp
+++ b/colorwheel.cpp
@@ -343,7 +343,6 @@ ColorwheelPrivate::paintColorwheel(int w, int h, qreal dpr)
     QPointF center(w/2.0, h/2.0);
     int diameter = std::min(w, h);
     int radius = diameter/2.0;
-   
     QPixmap colorwheel(w * dpr, h * dpr);
     colorwheel.fill(Qt::transparent);
     colorwheel.setDevicePixelRatio(dpr);
diff --git a/dragger.cpp b/dragger.cpp
index 1f53db4..565f7cc 100755
--- a/dragger.cpp
+++ b/dragger.cpp
@@ -82,8 +82,8 @@ DraggerPrivate::mapToGeometry()
     QSize size = mapToSize();
     int x = position.x() - size.width() / 2;
     int y = position.y() - size.height() / 2;
-    int width = baseRect.width();
-    int height = baseRect.height();
+    int width;
+    int height;
     
     QRect screenGeometry = screen->geometry();
     // left
diff --git a/icctransform.cpp b/icctransform.cpp
index 92fe12c..748651b 100644
--- a/icctransform.cpp
+++ b/icctransform.cpp
@@ -186,19 +186,19 @@ ICCTransform::ICCTransform::transformTo(QRgb color)
 }
 
 QImage
-ICCTransform::ICCTransform::transformTo(QImage image)
+ICCTransform::ICCTransform::transformTo(const QImage& image)
 {
     return p->transformTo(image, p->inputProfile, p->outputProfile);
 }
 
 QRgb
-ICCTransform::ICCTransform::transformTo(QRgb color, QString inputProfile, QString outputProfile)
+ICCTransform::ICCTransform::transformTo(QRgb color, const QString& inputProfile, const QString& outputProfile)
 {
     return p->transformTo(color, inputProfile, outputProfile);
 }
 
 QImage
-ICCTransform::transformTo(QImage image, QString inputProfile, QString outputProfile)
+ICCTransform::transformTo(const QImage& image, const QString& inputProfile, const QString& outputProfile)
 {
     return p->transformTo(image, inputProfile, outputProfile);
 }
diff --git a/icctransform.h b/icctransform.h
index cd0b1aa..59a10eb 100644
--- a/icctransform.h
+++ b/icctransform.h
@@ -20,9 +20,9 @@ class ICCTransform : public QObject
         QString inputProfile() const;
         QString outputProfile() const;
         QRgb transformTo(QRgb image);
-        QImage transformTo(QImage image);
-        QRgb transformTo(QRgb color, QString profile, QString outputProfile);
-        QImage transformTo(QImage image, QString profile, QString outputProfile);
+        QImage transformTo(const QImage& image);
+        QRgb transformTo(QRgb color, const QString& profile, const QString& outputProfile);
+        QImage transformTo(const QImage& image, const QString& profile, const QString& outputProfile);
    
     public Q_SLOTS:
         void setInputProfile(const QString& inputProfile);
diff --git a/mac.mm b/mac.mm
index 59500df..7636992 100755
--- a/mac.mm
+++ b/mac.mm
@@ -112,6 +112,7 @@ ColorSyncProfile grabColorSyncProfile(NSScreen* screen)
                 if (iccURLRef) {
                     colorSyncProfile.displayProfileUrl = CFURLCopyFileSystemPath(iccURLRef, kCFURLPOSIXPathStyle);
                 }
+                CFRelease(csProfileRef);
             }
             return colorSyncProfile;
         }
@@ -166,7 +167,11 @@ QImage grabImage(int x, int y, int width, int height, WId windowId)
         CGRect cgRect = (width < 0 || height < 0) ? CGRectInfinite : grabRect.toCGRect();
         const CGDisplayErr err = CGGetDisplaysWithRect(cgRect, maxDisplays, displays, &displayCount);
         if (err || displayCount == 0)
+        {
+            CFRelease(screenWindows);
+            CFRelease(grabWindows);
             return QImage();
+        }
 
         // if the grab size is not specified, set it to be the bounding box of all screens,
         if (width < 0 || height < 0) {
diff --git a/picker.cpp b/picker.cpp
index 2817796..f241c89 100755
--- a/picker.cpp
+++ b/picker.cpp
@@ -62,8 +62,8 @@ PickerPrivate::mapToGeometry()
     
     int x = position.x() - size.width() / 2;
     int y = position.y() - size.height() / 2;
-    int width = widget->width();
-    int height = widget->height();
+    int width;
+    int height;
     QRect screenGeometry = screen->geometry();
     // left
     if (x < screenGeometry.left()) {