fix #666,protect wheel action

--protect wheel actions in order to not trigger themselves
multiple times
--use a timer to achieve this goal in order to be able
to support also X11 systems that have previews enabled for
all windows (a behavior that normally breaks the isMinimized
state)

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

@@ -88,6 +88,7 @@ MouseArea{
     property bool inBouncingAnimation: false
     property bool inPopup: false
     property bool inRemoveStage: false
+    property bool inWheelAction: false
 
     property bool isActive: (IsActive === true) ? true : false
     property bool isDemandingAttention: (IsDemandingAttention === true) ? true : false
@@ -767,7 +768,7 @@ MouseArea{
     }
 
     onWheel: {
-        if (isSeparator || !root.mouseWheelActions
+        if (isSeparator || !root.mouseWheelActions || inWheelAction || inBouncingAnimation
                 || (latteDock && (latteDock.dockIsHidden || latteDock.inSlidingIn || latteDock.inSlidingOut))){
             return;
         }
@@ -778,28 +779,35 @@ MouseArea{
         if (angle > 12) {
             if (isLauncher) {
                 mouseEntered = false;
+                inWheelAction = true;
                 wrapper.runLauncherAnimation();
             } else if (isGroupParent) {
                 tasksWindows.activateNextTask();
             } else {
-                tasksModel.requestActivate(modelIndex());
+                var taskIndex = modelIndex();
+
+                if (isMinimized) {
+                    inWheelAction = true;
+                    tasksModel.requestToggleMinimized(taskIndex);
+                    wheelActionDelayer.start();
+                }
+
+                tasksModel.requestActivate(taskIndex);
             }
             //negative direction
         } else if (angle < 12) {
             if (isLauncher) {
-                //mouseEntered = false;
-                //wrapper.runLauncherAnimation();
+                // do nothing
             } 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());
+                if (isMinimized) {
+                    // do nothing
                 } else {
-                    tasksModel.requestActivate(modelIndex());
+                    var taskIndex = modelIndex();
+                    inWheelAction = true;
+                    tasksModel.requestToggleMinimized(taskIndex);
+                    wheelActionDelayer.start();
                 }
             }
         }
@@ -1346,6 +1354,15 @@ MouseArea{
         }
     }
 
+    // The best solution in order to catch when the wheel action ended is to
+    // track the isMinimized state, but when the user has enabled window previews
+    // at all times that flag doesnt work
+    Timer {
+        id: wheelActionDelayer
+        interval: 200
+        onTriggered: mainItemContainer.inWheelAction = false;
+    }
+
     ///Item's Removal Animation
     ListView.onRemove: TaskAnimations.TaskRealRemovalAnimation{ id: taskRealRemovalAnimation }