diff --git a/src/qml/level/LevelPreview.qml b/src/qml/level/LevelPreview.qml
index 06b5be0042fd7b62c9800df979084926fa68ba14..5acf0d4302dfe475c2a76809205185e56ff98419 100644
--- a/src/qml/level/LevelPreview.qml
+++ b/src/qml/level/LevelPreview.qml
@@ -51,7 +51,7 @@ TlevelPreviewItem {
             // HACK: keeping MouseArea inside PinchArea makes it working
             MouseArea {
                 anchors.fill: parent
-                onWheel: {
+                onWheel: wheel => {
                     if (wheel.modifiers & Qt.ControlModifier) {
                         if (wheel.angleDelta.y > 0)
                             zoom(true);
diff --git a/src/qml/nootini/AudioAnalyze.qml b/src/qml/nootini/AudioAnalyze.qml
index 90ea71ec20e6d9ac0e06bc8f7c3938e2054f0eb2..ac210cb747da065d2632a885750a19d5660d0495 100644
--- a/src/qml/nootini/AudioAnalyze.qml
+++ b/src/qml/nootini/AudioAnalyze.qml
@@ -48,7 +48,7 @@ TaudioAnalyzeItem {
 
         MouseArea {
             anchors.fill: parent
-            onWheel: {
+            onWheel: wheel => {
                 if (wheel.modifiers & Qt.ControlModifier) {
                     if (wheel.angleDelta.y > 0)
                         sc *= 1.0625;
diff --git a/src/qml/score/KeySignature.qml b/src/qml/score/KeySignature.qml
index a8b073e6a9d93619e2504a65ec3be626f4f85ab0..7925fa1314f2005c81c945534fc28aa98badda92 100644
--- a/src/qml/score/KeySignature.qml
+++ b/src/qml/score/KeySignature.qml
@@ -16,7 +16,7 @@ Item {
     readonly property var flatPos: [4, 1, 5, 2, 6, 3, 7]
 
     function accidOffset(c) {
-        var accidOff = 1;
+        let accidOff = 1;
         switch (c) {
         case Tclef.Bass_F:
         case Tclef.Bass_F_8down:
@@ -134,7 +134,7 @@ Item {
                 else
                     keyDown();
             }
-            onWheel: {
+            onWheel: wheel => {
                 if (wheel.angleDelta.y > 0)
                     deltaUp();
                 else if (wheel.angleDelta.y < 0)
diff --git a/src/qml/score/Staff.qml b/src/qml/score/Staff.qml
index 7cd8298a90006c953d68f5902127fb60d51644c7..e1beef8183fe9b8f7dfbce682101029841a212b9 100644
--- a/src/qml/score/Staff.qml
+++ b/src/qml/score/Staff.qml
@@ -5,7 +5,6 @@
 import Nootka 1.0
 import Nootka.Music
 import QtQuick 2.12
-import QtQuick.Controls 2.12
 import QtQuick.Window 2.12
 import Score 1.0
 
diff --git a/src/qml/sound/TempoBar.qml b/src/qml/sound/TempoBar.qml
index 0b1b037159c1a259e76c8b395f1d6e3fa7fd7fc6..7a229c6e9faddc361713117d9786fd2e7b070be5 100644
--- a/src/qml/sound/TempoBar.qml
+++ b/src/qml/sound/TempoBar.qml
@@ -48,7 +48,7 @@ Item {
                     }
                     tMenu.open();
                 }
-                onWheel: {
+                onWheel: wheel => {
                     if (!SOUND.metroRunning) {
                         if (wheel.angleDelta.y > 0)
                             SOUND.tempo = SOUND.tempo + (wheel.modifiers & Qt.ControlModifier ? 10 : 1);
@@ -210,11 +210,10 @@ Item {
 
     Connections {
         target: SOUND
-        function onCountdownPrepare() : void {
+        function onCountdownPrepare(tickCount) : void {
             if (SOUND.tickBeforePlay && !GLOB.singleNoteMode) {
                 if (!preCountItem) {
-                    var d = Qt.createComponent("qrc:/sound/CountdownItem.qml");
-                    preCountItem = d.createObject(score);
+                    preCountItem = Qt.createComponent("qrc:/sound/CountdownItem.qml").createObject(score);
                 }
                 preCountItem.tickCount = tickCount;
                 preCountItem.counter = 1;
diff --git a/src/qml/sound/TempoMenu.qml b/src/qml/sound/TempoMenu.qml
index b308ffd628fda33e14d1e967493b6dc3a95171f8..4846512b9a985d89e5c18130a0a0dfa115a7330e 100644
--- a/src/qml/sound/TempoMenu.qml
+++ b/src/qml/sound/TempoMenu.qml
@@ -95,7 +95,7 @@ Popup {
                 MouseArea {
                     anchors.fill: parent
                     z: -1
-                    onWheel: {
+                    onWheel: wheel => {
                         var ci = buTumb.currentIndex;
                         if (wheel.angleDelta.y > 0)
                             ci--;
@@ -282,7 +282,7 @@ Popup {
             enabled: !executor
 
             ButtonGroup {
-                buttons: radioRow.children
+                id: quantGr
             }
 
             MouseArea {
@@ -321,6 +321,7 @@ Popup {
                     text: "G"
                     textScale: 2
                     checked: SOUND.quantization === 6
+                    ButtonGroup.group: quantGr
                     onClicked: SOUND.quantization = 6
                     onHoveredChanged: NOO.setStatusTip(hovered ? quantTip : "", Item.TopLeft)
 
@@ -336,6 +337,7 @@ Popup {
                     text: "F"
                     textScale: 2
                     checked: SOUND.quantization === 12
+                    ButtonGroup.group: quantGr
                     onClicked: SOUND.quantization = 12
                     onHoveredChanged: NOO.setStatusTip(hovered ? quantTip : "", Item.TopLeft)