The search box at the top of a Group object will search the contents of the group. If the group is huge (thousands or tens of thousands of objects), then this search can be a bit slow.
The "+" button opens a picker that will display all objects that can be added. This searches over the entire system. It might seem counterintuitive that the system wide search is quicker than the group search, but we have certain indexes that make this work faster.
I can give you a few tips to make things easier and quicker:
- In R81.10 we made many improvements to the DB mechanisms, including searching. If you are not yet on that version in the Management, I strongly recommend an upgrade. Then try again and see if the experience has improved.
- If you want to remove a group reference to a certain object, you don't have to open the group and search for the object. Within the network object editor, there is a page for group membership (called "Groups") that you can use to add or remove that object from groups.
- If you have multiple references to an object that you want to remove (from many groups), you can also use the "Where Used" dialog directly. There is a "Replace" button in that dialog that you can use to switch references to this object with another object. You can also select "None" to remove references to this object. When you use this, you'll get little checkboxes near all the references and you can pick & choose which ones you want to remove.
I hope this helps.
Another tip that might help: if you are using huge groups of objects as block lists for malicious IPs (something that many customers do), a more efficient option is to switch to using dynamic IoC feeds. These require the Threat Prevention blades, but are more efficient, don't require policy installation to block more IPs and don't fill up your DB with many host objects.