Is it possible to disable the parent check for applications by default? I can ofcourse manually set it for all applications one by one, but maybe there’s an easier way.
Not in the sense you’re thinking of I believe. Under CFPs Security tab - Advanced - Application Behavior Analysis (ABA) there is the option Monitor Parent Application Leaks. CFPs Help says this concerning this option…
[b]Monitor Parent Application Leaks[/b] - Forces the firewall to check if there is a leaking attempt in the parent application. i.e. if [b]Process Injection[/b] is selected above, Comodo Firewall Pro will look for the parent application to see if there is a process injection in it before allowing the internet request.It is not recommend to turn this option off or avoid Parent checking, since this is the method that most well known firewall leak tests exploit & thus is an obvious risk to your security.
Too bad, but thanks for your reply anyway 
You might want to check back on 07-Jun, that’s the ETA for the new CFP 3 beta. It might be different in this regard, unfortunately I don’t remembered seeing a wish for this in CFPs Wish List… so, maybe not so different. Of course, the actual option might not even exist in CFP 3 for all I know. ;D