New error for search input with only outgoing Reg edges

[oliverfanderson]

We need develop a new error message/ability to handle the error when the query input protein has only outgoing regulatory edges

[oliverfanderson]

So, actually, this works. The error occurs when a source node has only incoming Reg edges. We cannot display which nodes regulate the source node directly when querying as of right now.

[oliverfanderson]

A few options to allow searching of incoming Reg edges:

• Flip order of source/target to get incoming reg edges
• Double click to expand neighbors
• Toggle incoming/outcoming in banner