Hello,
Most users of strongswan/ipsec are well aware of the intricacies of tunnel configuration, please don't confuse them with a new terminology for example "Local source ip" instead of leftsourceip, or at least specify that %config is a valid input in the electric help. This will avoid having to set "leftsourceip=%config" in the custom options field which doesn't work btw.
And please add a "unit selector box" to the IKE lifetime field and a runtime check for lifetime < 2 * margintime.
Regards,