Show DHCP leases table always

[DL6ER]

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Show DHCP leases table (will be empty) and allow editing of static leases also when DHCP server is not enabled. A number of users have reported that they hesitated to migrate away from their router's DHCP server to Pi-hole's since they were not aware of the possibility to add static leases.

Now we show the table always. The dynamic leases table will be empty as long as the DHCP server is disabled.

This template was created based on the work of udemy-dl.