The Select plugin provides the function of right-clicking to select multiple nodes.
import MindMap from 'simple-mind-map'
import Select from 'simple-mind-map/src/plugins/Select.js'
// import Select from 'simple-mind-map/src/Select.js' Use this path for versions below v0.6.0
MindMap.usePlugin(Select)
After registration and instantiation of MindMap, the instance can be obtained through mindMap.select.
Convert mouse position to position relative to the container el