@jwaltrip if you hover your mouse over the "i" for the legal DHCP servers, it pretty much explains its purpose.  On some routers or switches, its called "trusted dhcp".  This to make sure that no other dhcp server that someone may illegally put onto the network can provide addresses to try and steer users to another network.  

@Fleegle61 This does not completely answer the question.  I know what the I with the circle is

What I want to kniw is this the same as a Cisco IP helper?  

If I have 4 VLANS, and I set up a DHCP server on one of the VLANs, will this allow servers on other VLANS to get IPs from my DHCP server?

Also,, you can check both that and DHCP server at the same time...  Is this a flaw?

Edit:

I removed DHCP settings from the VLAN config, then check the d Legal DHCP servers, and pointed the IPs to my DHCP servers.

Media VLAN is on VLAN 20

DHCP servers are on VLAN 100.

DHCP not working.

Is there a way touse your own DHCP servers with Omada?

I opened a ticket with TP-Link.

there is currently no way, in a non-stand alone environment, to set up a DHCP IP helper using the GUI

They think it might be possible, but are investigatging.

To review what I want to do:  have DHCP server on VLAN 100, and have it provide IPs for VLANs 100,1,10,20,50

This is not directly supported by Omada, but aparently is supported if using the hardware in stand alone mode.