Thanks for contacting Syncfusion support.
We have check with your query. Based on the provided, we have prepared a simple sample to achieve your expected requirement.
In the below provided sample, we have injected the custom class to the HTML Sidebar element on the click event for button.
If we have misunderstood your query, then please provide us more details on your expected requirement like below.
· Any demo Screenshot of your requirement.
· Clear description.
· Your Code sample.
Please, let us know if you need any further assistance.
Shameer Ali Baig S.