To Create a Copy of a Level in the Open File

Select the open file from the tree.
Select the level(s) to be copied.
Right-click in the level list.
A pop-up menu opens.
Select Copy from the menu.
Select Paste from the menu.
A copy of the selected level(s) appears in the level list.
Select the copy of the level.
Right-click in the level list.
A pop-up menu opens.
Select Rename from the menu.
The level name takes the focus as an input field.
Type in the new name of the level and press <Enter> to accept the name.