mouse wheel to cycle through groupped tasks

plasmoid/contents/ui/TaskDelegate.qml

@@ -954,6 +954,41 @@ MouseArea{
         if(!inAnimation && !root.latteDock)
             checkListHovered.startDuration(3*units.longDuration);
     }
+
+    onWheel: {
+        var angle = wheel.angleDelta.y / 8;
+
+        //positive direction
+        if (angle > 12) {
+            if (isLauncher) {
+                mouseEntered = false;
+                wrapper.runLauncherAnimation();
+            } else if (isGroupParent) {
+                tasksWindows.activateNextTask();
+            } else {
+                activateTask();
+            }
+        //negative direction
+        } else if (angle < 12) {
+            if (isLauncher) {
+                mouseEntered = false;
+                wrapper.runLauncherAnimation();
+            } else if (isGroupParent) {
+                tasksWindows.activatePreviousTask();
+            } else {
+                if (IsMinimized === true) {
+                    var i = modelIndex();
+                    tasksModel.requestToggleMinimized(i);
+                    tasksModel.requestActivate(i);
+                } else if (IsActive === true) {
+                    tasksModel.requestToggleMinimized(modelIndex());
+                } else {
+                    tasksModel.requestActivate(modelIndex());
+                }
+            }
+        }
+    }
+
     ///////////////// End Of Mouse Area Events ///////////////////
 
     ///// Handlers for Signals /////

plasmoid/contents/ui/TaskWindows.qml

@@ -141,6 +141,7 @@ Item{
             }
         }
 
+        //the active window is the last one
         if (nextAvailableWindow >= childs.count) {
             nextAvailableWindow = 0;
         }
@@ -161,6 +162,51 @@ Item{
         tasksModel.requestActivate(tasksModel.makeModelIndex(index,nextAvailableWindow));
     }
 
+    //! function which is used to cycle activation into
+    //! a group of windows backwise
+    function activatePreviousTask() {
+        if (!mainItemContainer.isGroupParent) {
+            return;
+        }
+
+        windowsLocalModel.currentIndex = index;
+        var childs = windowsLocalModel.items;
+
+        //indicates than nothing was found
+        var prevAvailableWindow = -2;
+
+        for(var i=childs.count-1; i>=0; --i){
+            var kid = childs.get(i);
+            if (kid.model.IsActive === true) {
+                prevAvailableWindow = i - 1;
+                break;
+            }
+        }
+
+        //the active window is 0
+        if (prevAvailableWindow == -1) {
+            prevAvailableWindow = childs.count-1;
+        }
+
+        if (prevAvailableWindow === -2 && lastActiveWinInGroup !==-1){
+            for(var i=childs.count-1; i>=0; --i){
+                var kid = childs.get(i);
+                if (kid.model.LegacyWinIdList[0] === lastActiveWinInGroup) {
+                    prevAvailableWindow = i;
+                    break;
+                }
+            }
+        }
+
+        //no window was found
+        if (prevAvailableWindow === -2)
+            prevAvailableWindow = 0;
+
+        tasksModel.requestActivate(tasksModel.makeModelIndex(index,prevAvailableWindow));
+    }
+
+
+
     // keep a record of the last active window in a group
     Connections{
         target:tasksModel