I’m suggesting that the problem isn’t in your code, but in your “config.prc” file. If you’re not familiar with the file, it’s a configuration file that you should have received with Panda–although you can make your own if you want, and even set configuration values while the program is running.
There’s more information in the manual, starting here, I believe.
As to the post that you mention, take a look at the post just above it–enn0x mentions a “config variable”–that is, a variable in “config.prc”, named “bullet-filter-algorithm”.
Put another way, look for the file “config.prc” in your Panda installation, and look within that file for a variable named “bullet-filter-algorithm”. If it’s there, change it to “group-mask” (presuming that it’s not already set to that); if it’s not there, add it, with the same value.
(By the way, in order to link to a specific post on this forum, look for a small icon at the top-left of the post to which you want to link–it should look like a tiny page. That should link to the post, and copying that link should allow you to link others to it.)