Update and clean up QML imports

src/assets/assetlist/view/qml/assetList.qml

@@ -3,12 +3,13 @@
     SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
 */
 
-import QtQuick 2.11
-import QtQuick.Layouts 1.11
+import QtQuick 2.15
+import QtQuick.Layouts 1.15
+// TODO: we need QQC1 for TreeView (not available in QQC2, but in Qt6 again)
 import QtQuick.Controls 1.4
 import QtQuick.Controls.Styles 1.4
-import QtQuick.Window 2.2
-import QtQml.Models 2.11
+import QtQuick.Window 2.15
+import QtQml.Models 2.15
 import com.enums 1.0
 
 Rectangle {

src/assets/view/qml/AssetView.qml

@@ -3,12 +3,11 @@
     SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
 */
 
-import QtQuick 2.11
-import QtQuick.Controls 1.4
-import QtQuick.Controls.Styles 1.4
-import QtQuick.Window 2.2
-import QtQuick.Layouts 1.11
-import QtQml.Models 2.11
+import QtQuick 2.15
+import QtQuick.Controls 2.15
+import QtQuick.Window 2.15
+import QtQuick.Layouts 1.15
+import QtQml.Models 2.15
 
 Rectangle {
     id: assetRoot

src/effects/effectstack/view/qml/BuiltStack.qml

@@ -3,10 +3,9 @@
     SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
 */
 
-import QtQuick 2.11
-import QtQuick.Controls 1.4
-import QtQuick.Controls.Styles 1.4
-import QtQuick.Layouts 1.11
+import QtQuick 2.15
+import QtQuick.Controls 2.15
+import QtQuick.Layouts 1.15
 
 Rectangle {
     id: root

src/effects/effectstack/view/qml/EffectSlider.qml

 
-import QtQuick 2.11
-import QtQuick.Controls 1.4
+import QtQuick 2.15
+import QtQuick.Controls 2.15
 import QtQuick.Controls.Styles 1.4
-import QtQuick.Layouts 1.11
+import QtQuick.Layouts 1.15
 
 Item {
     id: sliderroot

src/effects/effectstack/view/qml/LiftGammaGain.qml

@@ -3,11 +3,10 @@
     SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
 */
 
-import QtQuick 2.11
-import QtQuick.Controls 1.4
-import QtQuick.Controls.Styles 1.4
+import QtQuick 2.15
+import QtQuick.Controls 2.15
 import Kdenlive.Controls 1.0
-import QtQuick.Layouts 1.11
+import QtQuick.Layouts 1.15
 
 Item {
     id: liftgammagain

src/monitor/view/Countdown.qml

@@ -3,8 +3,8 @@
     SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
 */
 
-import QtQuick.Controls 2.4
-import QtQuick 2.11
+import QtQuick.Controls 2.15
+import QtQuick 2.15
 
 Rectangle {
     id: counter

src/monitor/view/EffectToolBar.qml

@@ -4,8 +4,8 @@
     SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
 */
 
-import QtQuick.Controls 2.4
-import QtQuick 2.11
+import QtQuick.Controls 2.15
+import QtQuick 2.15
 
 MouseArea {
     id: barZone

src/monitor/view/MonitorRuler.qml

@@ -3,9 +3,9 @@
     SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
 */
 
-import QtQuick.Controls 2.4
+import QtQuick.Controls 2.15
 import Kdenlive.Controls 1.0
-import QtQuick 2.11
+import QtQuick 2.15
 import org.kde.kdenlive 1.0 as Kdenlive
 
     // Monitor ruler

src/monitor/view/MonitorToolButton.qml

@@ -3,8 +3,8 @@
     SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
 */
 
-import QtQuick 2.11
-import QtQuick.Controls 2.4
+import QtQuick 2.15
+import QtQuick.Controls 2.15
 
 
 ToolButton {

src/monitor/view/MultiScreenToolBar.qml

@@ -3,8 +3,8 @@
     SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
 */
 
-import QtQuick.Controls 2.4
-import QtQuick 2.11
+import QtQuick.Controls 2.15
+import QtQuick 2.15
 
 
 MouseArea {

src/monitor/view/OverlayCenter.qml

@@ -4,9 +4,8 @@
     SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
 */
 
-import QtQuick.Controls 1.4
-import QtQuick.Controls.Styles 1.4
-import QtQuick 2.11
+import QtQuick.Controls 2.15
+import QtQuick 2.15
 
 Item {
     id: overlay

src/monitor/view/OverlayCenterDiagonal.qml

@@ -4,9 +4,8 @@
     SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
 */
 
-import QtQuick.Controls 1.4
-import QtQuick.Controls.Styles 1.4
-import QtQuick 2.11
+import QtQuick.Controls 2.15
+import QtQuick 2.15
 
 Item {
     id: overlay

src/monitor/view/OverlayMinimal.qml

@@ -3,9 +3,8 @@
     SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
 */
 
-import QtQuick.Controls 1.4
-import QtQuick.Controls.Styles 1.4
-import QtQuick 2.11
+import QtQuick.Controls 2.15
+import QtQuick 2.15
 
 Item {
     id: overlay

src/monitor/view/OverlayStandard.qml

@@ -3,9 +3,8 @@
     SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
 */
 
-import QtQuick.Controls 1.4
-import QtQuick.Controls.Styles 1.4
-import QtQuick 2.11
+import QtQuick.Controls 2.15
+import QtQuick 2.15
 
 Item {
     id: overlay

src/monitor/view/OverlayThirds.qml

@@ -3,9 +3,8 @@
     SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
 */
 
-import QtQuick.Controls 1.4
-import QtQuick.Controls.Styles 1.4
-import QtQuick 2.11
+import QtQuick.Controls 2.15
+import QtQuick 2.15
 
 Item {
     id: overlay

src/monitor/view/SceneToolBar.qml

@@ -3,8 +3,8 @@
     SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
 */
 
-import QtQuick.Controls 2.4
-import QtQuick 2.11
+import QtQuick.Controls 2.15
+import QtQuick 2.15
 
 
 MouseArea {

src/monitor/view/kdenliveclipmonitor.qml

@@ -3,10 +3,10 @@
     SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
 */
 
-import QtQuick.Controls 2.4
-import QtQuick.Window 2.2
+import QtQuick.Controls 2.15
+import QtQuick.Window 2.15
 import Kdenlive.Controls 1.0
-import QtQuick 2.11
+import QtQuick 2.15
 import com.enums 1.0
 
 Item {

src/monitor/view/kdenlivemonitor.qml

@@ -3,10 +3,10 @@
     SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
 */
 
-import QtQuick.Controls 2.4
-import QtQuick.Window 2.2
+import QtQuick.Controls 2.15
+import QtQuick.Window 2.15
 import Kdenlive.Controls 1.0
-import QtQuick 2.11
+import QtQuick 2.15
 
 Item {
     id: root

src/monitor/view/kdenlivemonitorcornerscene.qml

@@ -3,7 +3,7 @@
     SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
 */
 
-import QtQuick 2.11
+import QtQuick 2.15
 
 Item {
     id: root

src/monitor/view/kdenlivemonitoreffectscene.qml

@@ -3,7 +3,7 @@
     SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
 */
 
-import QtQuick 2.11
+import QtQuick 2.15
 
 Item {
     id: root