The Structure-editor has already been presented shortly in the Compare Compounds by Drawing - subpage. As the database is not editable, except for the adding of own molecular-drawings in the advanced version (stock-data can't be edited) the main use of the structure-editor is for searching and comparing compounds / fragments by their drawing.
The structure-editor at a first glance:
The left part of the window consists of an 'attribute'-part above and and 'execute'-functions part below. Depending on the focus within the drawing, the appearance of these parts of the window will change.
If the focus is on an atom the left part of the editor window displays the functions that can be applied to an atom in the drawing.
If the focus is on a bond the left part of the editor window displays functions that can be applied to a bond in the drawing.