Disable user-select when the item is being dragged

Disable user-select on vue-grid-item when it's being dragged. If the user select text inside .vue-grid-item and starts moving it, that selection will prevent him from dragging the item. Setting user-select to none fixes the issue.

Author: ikbelkirasan

src/GridItem.vue

@@ -1,7 +1,7 @@
 <template>
     <div ref="item"
          class="vue-grid-item"
-         :class="{ 'vue-resizable' : resizable, 'resizing' : isResizing, 'vue-draggable-dragging' : isDragging, 'cssTransforms' : useCssTransforms, 'render-rtl' : renderRtl }"
+         :class="{ 'vue-resizable' : resizable, 'resizing' : isResizing, 'vue-draggable-dragging' : isDragging, 'cssTransforms' : useCssTransforms, 'render-rtl' : renderRtl, 'disable-userselect': isDragging }"
          :style="style"
     >
         <slot></slot>
@@ -75,6 +75,10 @@
         cursor: sw-resize;
         right: auto;
     }
+    
+    .vue-grid-item.disable-userselect {
+        user-select: none;
+    }
 </style>
 <script>
     import {setTopLeft, setTopRight, setTransformRtl, setTransform, createMarkup, getLayoutItem} from './utils';