"User Picker" doesnt display name?

[Markus]

The "User Picker" field doesnt display a name (like "Jon Doe") but only the internal identifier so something like "ni93894". This is obviously useless. 

How can we change this? Its possible to search for a name in the field, so it shouldnt be too hard to display a name, too?

[Raynard Rhodes]

This is a custom field? Do you have filtering enabled on it? Are you able to create another custom field and it functions the same, if it's a custom field?

[Markus]

Hello, yes it is a costum field. What kind of filtering do you mean?

[Raynard Rhodes]

Typically if there is not a filter everyone  should be available for selection by name. I want to see if you change the filtering to a specific group/person would it still show the same.

Jira Administration > System > Issues > Custom Field > nameOfCustomField

On the right hand side click the cog/wheel icon and select "Configure"

From here you should be able to choose a filtering.