Extentions not working in summary tab

Why extensions are not working in the summary tab?

You need to explain what you mean.

I want to run some code like in the picture below only in the summary tab but it does not get executed when I set custom location to “summary-view”

the same code runs in sales invoice view when I set the custom location to “sales-invoice-view” like in the picture below:

As far as I know, extensions has never worked in the Summary tab. Even if you select Everywhere as location, it will not appear in the Summary.

Plus, extension are placed under Obsolete Features, so I don’t think additional functionality will be added to it anytime soon.

Thanks for your input, will there be any alternative for extensions because I’m very dependent on it?