[Carnage]

I have just tested the ctrl+click to remove in 3 browsers: firefox, chrome and internet explorer it works in all of them. That said, I will update the core product to use checkboxes from now on since that'll work out easier for unselecting them. If you've removed the core product change the uninstall code to this

$q = $db->query_first("SELECT * FROM ". TABLE_PREFIX."pbpg_plugin WHERE dir='chess'"); 
$db->query_write("DELETE FROM ".TABLE_PREFIX."pbpg_pluginconfig WHERE pbpg_pluginid = $q[pbpg_pluginid]");
$db->query_write("DELETE FROM ". TABLE_PREFIX."pbpg_plugin WHERE pbpg_pluginid = $q[pbpg_pluginid]");

to forcibly remove the mod.

EDIT: Alternativly, you can update to the newest version of the core. Based on your feedback i've added tools to make removal much easier.