Error in release 1.12: Uncaught TypeError: Cannot read property 'popupEle' of undefined

[gzc]

Hi, after using 1.12.x I have this error and I find it's caused by this change in select.js

const _tree = this.refs.trigger.popupEle;

const _tree = this.trigger.popupEle;

To verify it, I tried to use 1.11.0 and it works.

Following is the error message when I use 1.12

Uncaught TypeError: Cannot read property 'popupEle' of undefined
at Object.onSelect [as onCheck] (eval at (index.js?d0470508c52c57157a58:19591), :1060:34)
at Tree.onCheck (eval at (index.js?d0470508c52c57157a58:8863), :654:13)
at TreeNode._this.onCheck (eval at (index.js?d0470508c52c57157a58:19621), :70:24)
at HTMLUnknownElement.boundFunc (eval at (index.js?d0470508c52c57157a58:5293), :63:9)
at Object.ReactErrorUtils.invokeGuardedCallback (eval at (index.js?d0470508c52c57157a58:5293), :69:16)
at executeDispatch (eval at (index.js?d0470508c52c57157a58:5269), :83:21)
at Object.executeDispatchesInOrder (eval at (index.js?d0470508c52c57157a58:5269), :106:5)
at executeDispatchesAndRelease (eval at (index.js?d0470508c52c57157a58:2929), :41:22)
at executeDispatchesAndReleaseTopLevel (eval at (index.js?d0470508c52c57157a58:2929), :52:10)
at Array.forEach ()
at forEachAccumulated (eval at (index.js?d0470508c52c57157a58:9475), :22:9)
at Object.processEventQueue (eval at (index.js?d0470508c52c57157a58:2929), :252:7)
at runEventQueueInBatch (eval at (index.js?d0470508c52c57157a58:21553), :15:18)
at Object.handleTopLevel [as _handleTopLevel] (eval at (index.js?d0470508c52c57157a58:21553), :25:5)
at handleTopLevelImpl (eval at (index.js?d0470508c52c57157a58:21559), :70:24)
at ReactDefaultBatchingStrategyTransaction.perform (eval at (index.js?d0470508c52c57157a58:3709), :141:20)

[yesmeck]

Can you reproduce this issue on http://react-component.github.io/tree-select/? If not, could you provide a reproduction link?