Hi, Nayan -
To make a PB response window resizable, you need to make use of a Windows API function, SetWindowLong. The thread below contains details and refers to other related threads as well.
https://community.appeon.com/index.php/qna/q-a/resize-a-single-pfc-window-inherited-from-w-response
Please note that making a response window resizable does NOT automatically make the contents of the window resize. That requires code. If your application is built upon the PowerBuilder Foundation Class (PFC) framework, there is a Window Resize service you can use for this. I'm pretty sure Chris's STD framework also provides similar functionality.
Late last week I published in the PowerBuilder section of CodeXchange a sample application for displaying PB enumerations, and this app contains a stand-alone version of a Window Resize service which is based off of the PFC implementation. You are welcome to make use of it if you wish. You can download this app in the CodeXchange section of the Appeon Community website.
Your comment "According to parent window." is a little cryptic, so I'm not sure what you mean. Please explain in more detail what you mean by this?
Best regards, John