* optimize UI for kanban and fix drop rules not work.

module/execution/js/kanban.js

@@ -1197,7 +1197,7 @@ function initKanban($kanban)
         onRenderLaneName:  renderLaneName,
         onRenderHeaderCol: renderHeaderCol,
         onRenderCount:     renderCount,
-        droppable:         groupBy == 'default' ? {target: findDropColumns, finish:handleFinishDrop, mouseButton: 'left'} : false,
+        droppable:         groupBy == 'default' ? {target: findDropColumns, finish:handleFinishDrop} : false,
     });
 
     $kanban.on('click', '.action-cancel', hideKanbanAction);

module/execution/js/taskkanban.js

@@ -1013,8 +1013,7 @@ $(function()
         droppable:
         {
             target:       findDropColumns,
-            finish:       handleFinishDrop,
-            mouseButton: 'left'
+            finish:       handleFinishDrop
         },
         onRenderHeaderCol: renderHeaderCol,
         onRenderLaneName:  renderLaneName,

module/kanban/js/view.js

@@ -1251,8 +1251,7 @@ function initKanban($kanban)
         droppable:
         {
             target:       findDropColumns,
-            finish:       handleFinishDrop,
-            mouseButton: 'left'
+            finish:       handleFinishDrop
         },
     });
 

module/productplan/js/browse.js

@@ -67,8 +67,7 @@ $(function()
             droppable:
             {
                 target:      findDropColumns,
-                finish:      handleFinishDrop,
-                mouseButton: 'left'
+                finish:      handleFinishDrop
             }
         });
 

module/project/js/kanban.js

@@ -208,8 +208,7 @@ $(function()
             {
                 selector:     '.kanban-card:not(.execution-item)',
                 target:       findDropColumns,
-                finish:       handleFinishDrop,
-                mouseButton: 'left'
+                finish:       handleFinishDrop
             },
         });
     });