simplify TaskWindows and avoid a crash

--during dragging the DelegateModel inside
TaskWindows may not catch up with TasksModel
modelIndex() function and that could create
crashes. In order to avoid such crashes the
DelegateModel is not updated during dragging
and we give it also a little time to update
after the dragging has finished.

plasmoid/package/contents/ui/task/TaskWindows.qml

@@ -27,7 +27,17 @@ import QtQml.Models 2.2
 
 Item{
     id: windowsContainer
-    property int windowsCount: 0
+    property int windowsCount: {
+        if (isLauncher) {
+            return 0;
+        }
+
+        if (isGroupParent) {
+            return windowsRepeater.count;
+        }
+
+        return 1;
+    }
 
     property bool isLauncher: IsLauncher ? true : false
     property bool isStartup: IsStartup ? true : false
@@ -35,44 +45,67 @@ Item{
 
     property int lastActiveWinInGroup: -1
 
-    onIsLauncherChanged: updateCounter();
-    //  onIsStartupChanged: updateCounter();
-    //    onIsWindowChanged: updateCounter();
-
     //states that exist in windows in a Group of windows
     property bool hasMinimized: false;
     property bool hasShown: false;
     property bool hasActive: false;
 
-    //FIXME: For some reason the index is not updated correctly in some cases (e.g. window dragging, repositioning launchers)
-    // and this way much beautiful information are lost, an activity change back and return,
-    // it fixes this sometimes...
     Repeater{
+        id: windowsRepeater
         model:DelegateModel {
             id: windowsLocalModel
             model: tasksModel
 
-            //! This is a little suspicious code for crashes
-            //! during dragging or when the dragging ends. It needs
-            //! investigation to be confirmed or not
-            rootIndex: tasksModel.makeModelIndex(currentIndex >=0 ? currentIndex : index)
-
-            property int currentIndex: -1
-
             delegate: Item{
                 readonly property string title: display !== undefined ? display : ""
                 readonly property bool isMinimized: IsMinimized === true ? true : false
+                readonly property bool isActive: IsActive === true ? true : false
 
-                onIsMinimizedChanged: windowsContainer.initializeStates();
+                onIsMinimizedChanged: windowsContainer.updateStates();
+                onIsActiveChanged:  {
+                    if (isActive) {
+                        windowsContainer.lastActiveWinInGroup = (LegacyWinIdList!==undefined ? LegacyWinIdList[0] : 0);
+                    }
+                    windowsContainer.updateStates();
+                }
+            }
+
+            Component.onCompleted: {
+                rootIndex = mainItemContainer.modelIndex();
             }
         }
+    }
 
-        onCountChanged:{
-            windowsContainer.updateCounter();
+    Connections{
+        target: mainItemContainer
+        onItemIndexChanged: windowsContainer.updateStates();
+    }
+
+    Connections{
+        target: root
+        onInDraggingPhaseChanged: windowsContainer.updateStates();
+    }
+
+    //! try to give the time to the model to update its states in order to
+    //! avoid any suspicious crashes during dragging grouped tasks that
+    //! are synced between multiple panels/docks. At the same time in updateStates()
+    //! function we block any DelegateModel updates when the user is dragging
+    //! a task because this could create crashes
+    Timer{
+        id: initializeStatesTimer
+        interval: 200
+        onTriggered: windowsContainer.initializeStates();
+    }
+
+    function updateStates() {
+        if (!root.inDraggingPhase) {
+            initializeStatesTimer.start();
         }
     }
 
     function initializeStates(){
+        windowsLocalModel.rootIndex = mainItemContainer.modelIndex();
+
         hasMinimized = false;
         hasShown = false;
         hasActive = false;
@@ -93,7 +126,6 @@ Item{
     }
 
     function checkInternalStates(){
-        windowsLocalModel.currentIndex = index;
         var childs = windowsLocalModel.items;
 
         for(var i=0; i<childs.count; ++i){
@@ -110,22 +142,14 @@ Item{
     }
 
     function windowsTitles() {
+        windowsLocalModel.rootIndex = mainItemContainer.modelIndex();
         var result = new Array;
-
-        windowsLocalModel.currentIndex = index;
         var childs = windowsLocalModel.items;
 
         for(var i=0; i<childs.count; ++i){
             var kid = childs.get(i);
             var title = kid.model.display
 
-            //console.log(title);
-            // FIXME: we may need a way to remove the app name from the end
-            /*   var lst = title.lastIndexOf(" - ");
-            if (lst > 0) {
-                 title = title.substring(0, lst);
-             }*/
-
             result.push(title);
         }
 
@@ -135,13 +159,13 @@ Item{
     //! function which is used to cycle activation into
     //! a group of windows
     function activateNextTask() {
+        windowsLocalModel.rootIndex = mainItemContainer.modelIndex();
+
         if (!mainItemContainer.isGroupParent) {
             return;
         }
 
-        windowsLocalModel.currentIndex = index;
         var childs = windowsLocalModel.items;
-
         var nextAvailableWindow = -1;
 
         for(var i=0; i<childs.count; ++i){
@@ -178,11 +202,12 @@ Item{
     //! function which is used to cycle activation into
     //! a group of windows backwise
     function activatePreviousTask() {
+        windowsLocalModel.rootIndex = mainItemContainer.modelIndex();
+
         if (!mainItemContainer.isGroupParent) {
             return;
         }
 
-        windowsLocalModel.currentIndex = index;
         var childs = windowsLocalModel.items;
 
         //indicates than nothing was found
@@ -218,69 +243,11 @@ Item{
         tasksModel.requestActivate(tasksModel.makeModelIndex(index,prevAvailableWindow));
     }
 
-
-
-    // keep a record of the last active window in a group
-    Connections{
-        target:tasksModel
-        onActiveTaskChanged:{
-            if (!mainItemContainer.isGroupParent) {
-                return;
-            }
-
-            windowsLocalModel.currentIndex = index;
-            var childs = windowsLocalModel.items;
-
-            for(var i=0; i<childs.count; ++i){
-                var kid = childs.get(i);
-                if (kid.model.IsActive === true) {
-                    windowsContainer.lastActiveWinInGroup = kid.model.LegacyWinIdList ? kid.model.LegacyWinIdList[0] : 0;
-                    break;
-                }
-            }
-        }
-    }
-
     Component.onCompleted: {
         mainItemContainer.checkWindowsStates.connect(initializeStates);
-        updateCounter();
     }
 
     Component.onDestruction: {
         mainItemContainer.checkWindowsStates.disconnect(initializeStates);
     }
-
-    function updateCounter(){
-        //    console.log("--------- "+ index+" -------");
-        if(index>=0){
-            if(IsGroupParent){
-                windowsLocalModel.currentIndex = index;
-                var tempC = windowsLocalModel.count;
-
-                if (tempC == 0){
-                    if(isLauncher){
-                        windowsCount = 0;
-                    }
-                    else if(isWindow || isStartup){
-                        windowsCount = 1;
-                    }
-                }
-                else{
-                    windowsCount = tempC;
-                }
-            }
-            else{
-                if(isLauncher){
-                    windowsCount = 0;
-                }
-                else if(isWindow || isStartup){
-                    windowsCount = 1;
-                }
-            }
-
-            initializeStates();
-        }
-
-    }
-
 }