Add kineticScrollingDeceleration setting

src/backend/user_files.py

@@ -267,6 +267,7 @@ class UISettings(JSONDataFile):
             "hideMembershipEvents": False,
             "hideUnknownEvents": True,
             "kineticScrollingMaxSpeed": 2500,
+            "kineticScrollingDeceleration": 1500,
             "markRoomReadMsecDelay": 200,
             "maxMessageCharactersPerLine": 65,
             "ownMessagesOnLeftAboveWidth": 895,

src/gui/Base/HFlickable.qml

@@ -5,6 +5,7 @@ import QtQuick.Controls 2.12
 
 Flickable {
     maximumFlickVelocity: window.settings.kineticScrollingMaxSpeed
+    flickDeceleration: window.settings.kineticScrollingDeceleration
 
     ScrollBar.vertical: HScrollBar {
         visible: parent.interactive

src/gui/Base/HGridView.qml

@@ -75,6 +75,7 @@ GridView {
     preferredHighlightEnd: height / 2 + currentItemHeight / 2
 
     maximumFlickVelocity: window.settings.kineticScrollingMaxSpeed
+    flickDeceleration: window.settings.kineticScrollingDeceleration
 
 
     highlight: Rectangle {

src/gui/Base/HKineticScrollingDisabler.qml

@@ -7,9 +7,6 @@ MouseArea {
 
     property Flickable flickable: parent
 
-    // Used to get default flickDeceleration value
-    readonly property Flickable dummy: Flickable {}
-
     function getNewPosition(flickable, wheel) {
         // wheel.pixelDelta will be available on high resolution trackpads.
         // Otherwise use wheel.angleDelta, which is available from mouses and
@@ -60,6 +57,9 @@ MouseArea {
     Binding {
         target: flickable
         property: "flickDeceleration"
-        value: mouseArea.enabled ? 0 : dummy.flickDeceleration
+        value:
+            mouseArea.enabled ?
+            0 :
+            window.settings.kineticScrollingDeceleration
     }
 }

src/gui/Base/HListView.qml

@@ -87,7 +87,7 @@ ListView {
     preferredHighlightEnd: height / 2 + currentItemHeight / 2
 
     maximumFlickVelocity: window.settings.kineticScrollingMaxSpeed
-
+    flickDeceleration: window.settings.kineticScrollingDeceleration
 
     highlight: Rectangle {
         color: theme.controls.listView.highlight