If the Document Type's available Keyword Types are displayed in a collapsed state with a + sign, the Keyword Types are part of a Multi-Instance Keyword Type Group.
Multi-Instance Keyword Type Groups can display in a collapsed state with only the name of the Multi-Instance Keyword Type Group showing, or they can display with the Keyword Values in the Keyword Type Group expanded.
If the Multi-Instance Keyword Type Group is displayed in a collapsed state, click the Expand symbol next to the first Keyword Type or press Ctrl + O to expand it to show the entire group.