These menu entries allow you to manually build tree segments. This can be particularly handy to investigate what files might exist or to directly build a tree which matches a known server configuration.
In general the Insert command will allow you to insert a new directory or file under the currently selected segment. The Delete command will remove the currently selected segment and all of the directories and files under that branch of the tree.
You may find it easier to utilize the URL Capture Bar to build tree branches than Insert.
There are a few restrictions on where a directory or file may be inserted :
Inserted segments will have a Pre-Text value of "New" with no fusk data or Post-Text. If a segment with matching text already exists under the selected segment then the Pre-Text of the new segment will be "XXXNew" where "XXX" is the first number (starting with 001) for which there is not already an existing segment.
Use the Modify menu option to change the default segment fields to the values you wanted for the new segment.
There are only a couple of restrictions when deleting a segment:
Delete can be particularly useful if you accidently add a reference to a web page rather than an image or for tailoring fusker collections you have downloaded from other sources to contain only the content which interests you.
Inserting or Deleting a segment does not make use of any user configurations.