Not showing arrow

[jstray]

In the default configuration, or with showArrow=true, I'm not seeing an arrow.

        <Collapse>
          <Panel header='Output'>
            <DataGrid idProperty="index" dataSource={tableData} columns={columns} />
          </Panel>
        </Collapse>

This is using Bootstrap 4, if that makes a difference.

[jstray]

Ah, needed to include the CSS:

require('rc-collapse/assets/index.css');

Would have been helpful to see this in the examples.

[shepherdwind]

I add this to doc file README.md now, It is seems a lot of this kind problem.