Is it possible to debug (breakpoints, watch vars) scripts belonging to script extentions?

I did not encapsulate the source code yet.

According to the page (https://support.smartbear.com/testcomplete/docs/working-with/extending/script/debugging.html):

Note, however, that debugging packaged extensions (.tcx files) is not possible, because TestComplete locks them when it is running, so you will be unable to update the extension file without leaving TestComplete. This problem does not apply to unpacked script extensions.

But I still cannot debug it with unpacked. why?