解决drop弹出动画异常

src/components/select/dropdown.vue

@@ -46,6 +46,9 @@
                                 computeStyle:{
                                     gpuAcceleration: false,
                                 }
+                            },
+                            onCreate:()=>{
+                                this.resetTransformOrigin();
                             }
                         });
                     });
@@ -64,6 +67,10 @@
                         }
                     }, 300);
                 }
+            },
+            resetTransformOrigin() {
+                let placement = this.popper.popper.getAttribute('x-placement').split('-')[0];
+                this.popper.popper.style.transformOrigin = placement==='bottom'?'center top':'center bottom';
             }
         },
         created () {

src/components/select/select.vue

@@ -35,7 +35,7 @@
                 <Icon type="arrow-down-b" :class="[prefixCls + '-arrow']" v-if="!remote"></Icon>
             </slot>
         </div>
-        <transition :name="transitionName">
+        <transition name="transition-drop">
             <Drop
                 :class="dropdownCls"
                 v-show="dropVisible"