Fix tab order after expanding categories or using search

This reimplements the behavior of pressing tab/backtab to force the correct order of items in the listview.

resources/qml/Settings/SettingCheckBox.qml

@@ -11,13 +11,13 @@ import UM 1.2 as UM
 SettingItem
 {
     id: base
+    property var focusItem: control
 
     contents: MouseArea
     {
         id: control
         anchors.fill: parent
         hoverEnabled: true
-        activeFocusOnTab: true
 
         property bool checked:
         {
@@ -62,6 +62,15 @@ SettingItem
             propertyProvider.setPropertyValue("value", !checked);
         }
 
+        Keys.onTabPressed:
+        {
+            base.setActiveFocusToNextSetting(true)
+        }
+        Keys.onBacktabPressed:
+        {
+            base.setActiveFocusToNextSetting(false)
+        }
+
         onActiveFocusChanged:
         {
             if(activeFocus)