I'm on the same versions except IJ CE

ok I've got it. Breakpoints don't work in a namespace if you eval code in that ns using "send form to REPL"

you have to eval code from another namespace because otherwise it can't find the information needed and the breakpoint turns into a grayed-out icon

so it looks like breakpoints are limited to code outside the namespace from which you're evaluating code

No, that’s not right - the main problem is generally line numbers in the generated code, which can change if you’re editing and sending only parts of a namespace (i.e. with send form).

If you’re debugging a namespace, I always recommend re-sending the whole file to ensure all the line numbers are correct.

I tried that (select-all, send to REPL) many times in different ways and it didn't work for me. Then I tried doing (use :reload this-namespace) in my (comment) block in the same file and it worked!

Select all and send is not the same thing, you want to use Tools -> REPL -> Load file in REPL which uses load-file and correctly creates the line numbers in the bytecode. Or require :reload will work too, anything that causes the whole namespace to be loaded using load-file.

got it. It works

thanks for your help!