persistent cheatsheet tabs (closes #2681)

dots/.config/quickshell/ii/modules/common/Persistent.qml

@@ -63,6 +63,10 @@ Singleton {
                 property real temperature: 0.5
             }
 
+            property JsonObject cheatsheet: JsonObject {
+                property int tabIndex: 0
+            }
+
             property JsonObject sidebar: JsonObject {
                 property JsonObject bottomGroup: JsonObject {
                     property bool collapsed: false

dots/.config/quickshell/ii/modules/ii/cheatsheet/Cheatsheet.qml

@@ -4,6 +4,7 @@ import qs.modules.common.widgets
 import QtQuick
 import QtQuick.Controls
 import QtQuick.Layouts
+import Qt.labs.synchronizer
 import Qt5Compat.GraphicalEffects
 import Quickshell.Io
 import Quickshell
@@ -135,7 +136,10 @@ Scope { // Scope
                         ToolbarTabBar {
                             id: tabBar
                             tabButtonList: root.tabButtonList
-                            currentIndex: swipeView.currentIndex
+
+                            Synchronizer on currentIndex {
+                                property alias source: swipeView.currentIndex
+                            }
                         }
                     }
 
@@ -144,8 +148,11 @@ Scope { // Scope
                         Layout.topMargin: 5
                         Layout.fillWidth: true
                         Layout.fillHeight: true
-                        currentIndex: tabBar.currentIndex
                         spacing: 10
+                        currentIndex: Persistent.states.cheatsheet.tabIndex
+                        onCurrentIndexChanged: {
+                            Persistent.states.cheatsheet.tabIndex = currentIndex;
+                        }
 
                         implicitWidth: Math.max.apply(null, contentChildren.map(child => child.implicitWidth || 0))
                         implicitHeight: Math.max.apply(null, contentChildren.map(child => child.implicitHeight || 0))