The LavaPE declaration view is associated with three specific toolbars, the "tree operations bar", the actual "declarations bar", and the "details bar"..
The tree operations toolbar
provides the following operations (from left to right), which partly apply to a single tree node, partly to the sub-tree starting at the current selection, partly to the entire declaration tree:
Expand/open the whole sub-tree starting at the current selection.
Contract the selected sub-tree.
Show/hide the empty optional direct sub-nodes of the current node.
Show/hide empty optional elements within the entire sub-tree starting at the current selection.
Open/close the (tabbed) utility window (used particularly for displaying error messages and comments).
Go to the next/preceding comment in the declaration tree.
Go to the next/preceding error in the declaration tree.
Check the entire Lava program file, including all execs, for errors. (This is done automatically when opening a Lava program file, but not on every individual tree editing operation. In the latter case only the declarations are checked again.)
Check this and all included files.
Run the current Lava program.
provides the following operations (from left to right):
Specify a new "include file" for the current Lava file, which will appear then in the "include view" left of the tree view window.
Declare a new package,
Declare a new initiator,
Declare a new class,
Declare a new implementation,
Declare a new component object specification,
Declare a new component object implementation,
Declare a new set of objects of a certain class,
Declare a new enumeration type,
Declare a new virtual type,
Declare a new member function of an class or implementation,
Declare a new member variable of an class or implementation or an input or output parameter of a function.
Declare a new enumeration item.
Make GUI service from selected class.
provides the following operations (from left to right):
Open the property sheet of the selected Lava entity or open the selected exec or invariant for editing.
Attach/edit a comment to the selected Lava entity.
Jump to the declaration of the selected Lava entity.
Go to implementation (of selected function or class).
Return to the original Lava entity (after "jump to declaration").
Find references to selected symbol in all open or included Lava files. (Double-click a list entry to see the place where the corresponding symbol is referenced.)
Find symbol by name.
Open the "override view" in order to override/specialize the features or virtual types of the selected class or package.
Override the feature or virtual type selected in the override view.
Open the (WYSIWYG) form view and the "form structure tree view" associated with a "Lava GUI implementation".
Insert text between the fields of a form (each of which may be decorated also individually with "prefix" and "suffix" texts).
Insert optional item in form view.
Delete optional item in form view.Context-sensitive help
Use the context-sensitive help of LavaPE to get information about individual menu items and operator and keyword tool buttons: Click the context help tool button 
, drag it to the respective Lava tool button or menu item for which you want to get an explanation and drop it there.
How to insert/delete/edit Lava entities
The declaration tree consists of two alternating kinds of layers: 1. declaration layers containing the actual entity declarations, and 2. category layers that serve for the distinction between several kinds of nested, subordinate declarations for some entities, for instance virtual types, nested declarations, features, execs/invariants, or input/output parameters of functions or initiators.
If you select any tree node of the Lava declaration view then the enabled tool buttons on the declaration toolbar indicate which declarations may be inserted after the selected declaration node or below the selected category node by clicking these buttons. If you click the scissors 
then the selected declaration is deleted (together with the entire sub-tree that may beginning at this node) and copied to the clipboard. If you press the DEL key instead of clicking the scissors then the declaration is deleted but not written to the clipboard.
If you double-click the text to the right of an entity icon then the property sheet of the entity is opened for editing. Alternatively you can select the declaration node and then click the spectacles to open the property sheet.
How to insert/delete optional parts
You can click the "Show empty optionals" tool button 
on a declaration node to toggle the visibility of its empty category nodes (having no subordinate nodes). The same can be achieved for an entire sub-tree by using the "Show/hide all empty optionals" buttons 
instead.
How to insert, edit and step through comments
The yellow balloon may be clicked to add or change a comment that is associated with the currently selected tree node of the declaration view. The icon of a commented tree node has a little yellow bubble on the right side, for instance 
. The two buttons may be used to open/close the comments window and to step from comment to comment in forward or backward direction. If the comments window is open and you click a commented tree node then the associated comment will be shown in the comments window.
Error navigation
The two buttons may be used to open/close the error window and to step from error to error in forward or backward direction. The icon of an erroneous tree node has a little red rectangle on the right side, for instance 
.
Cut/copy/paste and drag/drop
Cut/copy/paste work in the usual way, using the clipboard of MS Windows. Proper enabling/disabling of the corresponding buttons 
combined with subsequent checks that are performed anyway after each edit operation prevent inadmissible operations.
Drag-and-drop is also available in the declaration view. For instance you can rearrange the declarations of a package, the items of an enumeration type, or the features of an class or implementation simply by drag-and-drop. To shift an item to the first position on its respective tree layer you can drag-and-drop it to the parent node. The Shift key can be used in the usual way to select a sequence of contiguous items.
Note that "cut" deletes a Lava entity and a subsequent "paste" creates a new one in any case, having a new internal ID, whereas the "move" mode of drag-and-drop (press the Shift key while dragging!) retains the identity of the moved Lava entity.
If you drag and drop between different Lava files then all existing references to the moved Lava entity are updated accordingly, provided they are contained in a file that is open at that moment in the Lava declaration editor.
For drag-and-drop the default operation is move. Press Ctrl after starting the drag operation to enforce a copy. You can also select multiple items (using the Ctrl key) before starting the drag operation. In this case don't release the left mouse button after the last selection but rather start dragging immediately. The pressed or released state of the Ctrl button (which means copy or move, respectively) matters only at the moment of the drop operation.
Use the "Undo" and "Redo" buttons 
to undo or redo individual edit operations in any of the LavaPE views step by step.
Drag-and-drop operations between different Lava files modify these files in a single edit step. Up to Lava release 0.6.3 undo/redo had to be applied to each of these files separately. Release 0.6.4 has introduced synchronized undo/redo support for such operations: You have to apply undo/redo only to one of these files to undo/redo the edit step also in the other file. But note that you can undo/redo edit steps only in strictly reverse order. So if you have applied further edit steps to one or both of these files then you have to undo/redo these before you can undo/redo the drag-and-drop operation between the files, or else you have to resort to manual "forward" repair steps.
Go to declaration / return to reference
If the declaration of a Lava entity references another Lava entity then you can double-click the icon left of the actual declaration to jump to the referenced entity's declaration. Alternatively you can select the respective declaration node and click the "Go to declaration" button . If the selected declaration references more than one other entity then a small combo box is popped up from which you can select where to go.
Use the "Return to reference" button to follow the sequence of such "Go to declaration" operations in backward direction (= back to the locations from where you came). Both operations may jump forth and back between exec and declaration views and even between different ("included") Lava documents.
See also override view.