Customize the left pallette

Hello,
I can set some palette items,like UserTask,ServiceTask.
But I can not set the intermediate, like TimeEventDefinition. When I drag the TimeEventDefinition, it show error img and I can not create the TimeEventDefinition in canvas.
I do not know which file to set the rules.
Do you have any good ideas?
image
image

你好,请问你这个前端怎么做的? 能给源码或者github的项目看下吗? 我也想做一个bpmn在线编排的前端界面,但是不知道怎么入手。

Please keep the communication in English so others can participate.

okay, i’m a new comer here, and want to know how to create a bpmn canvas used bpmnjs at my frontend web application(based on reactjs).

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