:) Code::Blocks is a awesome development tool, I'm happy using it, but in the new 20.03 version I noticed that the symbol browser don't work, apparently by design has been disable. The symbol browser is a really helpful feature that I would like to see functioning again.
Download the last nightly (https://forums.next.codeblocks.org/index.php/topic,24613.0.html) ZIP files, unzip them in a folder of your choice and you will have the Symbol Browser again.