update Poptip options

src/components/base/popper.js

@@ -32,13 +32,10 @@ export default {
                     modifiers: {
                         computeStyle:{
                             gpuAcceleration: false,
+                        },
+                        preventOverflow :{
+                            boundariesElement: 'body'
                         }
-                    },
-                    preventOverflow :{
-                        boundariesElement: 'body',
-                    },
-                    flip :{
-                        boundariesElement: 'body',
                     }
                 };
             }
@@ -89,10 +86,7 @@ export default {
             }
 
             options.placement = this.placement;
-            
-            if (!options.modifiers) {
-                options.modifiers = {};
-            }
+
             if (!options.modifiers.offset) {
                 options.modifiers.offset = {};
             }