CIDR Network Ranges do not seem to work for access to specific services

Question

I have just tried to install an SG135, and thought I would create some Rules with specific source groups. 
 After a lengthy investigation I have found the following; 
 CIDR network ranges (x.x.x.x/y) do not work as expected for inbound Rules; 
 this I found did not work for these areas 
 SSH Access 
 Webadmin 
 DNAT Rule 
 Firewall Rules 
 
 Is there a work around for this (other than adding individual IP addresses in to the rule, as I know this does work but will become cumbersome to manage)? 
 is this a known issue? 
 
 any help greatly appriciated

apijnappels · Accepted Answer

I'm not sure if i understand you correctly, but what I have configured in allowed networks for webadmin access works: 
 
 Pretty sure I have more places where I specifically use network definitions and they also work. Or I am not understanding you in which case you might be able to better explain the problem (and maybe add some screenshots).