How can I record resizable box in Katalon studio?

Resizable_2

Any recorder is going to record actions, like click and keyboard activity.

What is it you want to automate?

@Russ_Thomas
I want to automate it, when I pull the inner form. When I run test case, system run test case successfully. But, system show original form (first figure). System doesn’t expand inner form (second figure). Please answer me. Thank you.

It’s hard to help you with such limited information.

If those are HTML elements (e.g. DIVs) or even HTML canvas elements then you can automate them using Robot API.

For HTML elements, you might also try the WebUI drag functions.

https://www.guru99.com/using-robot-api-selenium.html
https://docs.oracle.com/javase/8/docs/api/java/awt/Robot.html