refactor: remove unnecessary code

Author: SSShooter

package.json

@@ -1,6 +1,6 @@
 {
   "name": "mind-elixir",
-  "version": "4.1.5",
+  "version": "4.2.0",
   "type": "module",
   "description": "Mind elixir is a free open source mind map core.",
   "keywords": [

src/dev.ts

@@ -29,7 +29,8 @@ const options: Options = {
   // mouseSelectionButton: 2,
   draggable: true,
   editable: true,
-  contextMenu: false,
+  // if you set contextMenu to false, you should handle contextmenu event by yourself, e.g. preventDefault
+  contextMenu: true,
   contextMenuOption: {
     focus: true,
     link: true,

src/mouse.ts

@@ -80,7 +80,4 @@ export default function (mind: MindElixirInstance) {
     if (e.button !== mouseMoveButton) return
     dragMoveHelper.clear()
   })
-  mind.map.addEventListener('contextmenu', e => {
-    e.preventDefault()
-  })
 }