There are three 'editing areas' and two 'passover areas'. The editing areas are, as one might expect, where the tree structure, its operations and conditions can be edited. The passover areas are used to display information as the mouse passes over objects in the tree editing area. If the mouse passes over a box with a condition, the text of that condition is displayed in the conditions passover area. If the mouse passes over a box that contains operations, the text of all those operations is displayed in the operations passover area.
You can adjust the sizes of the areas by dragging their frame borders. However you can hide some of the areas completely by using the following toolbar buttons:
Hides all areas except the tree editing area, so that it fills the window
Hides both the passover areas
Hides the operations and conditions editing areas
The default arrangement with all the areas on view
Note: The proportions allocated to the various areas can be stored for each
file, so that when the file is re-opened in the future it has the same apperance.
Alternatively the 
toolbar button will reset the proportions
to default values.