The Diagram Editor Sidebar provides an alternative view of the model shown in the drawing area. The tree view at the top shows the object types in this graph type, with the instances of those types as leaves (including subtype instances, if the type is abstract). The property sheet at the bottom shows the property values of the most recently selected element of the graph, or those of the graph itself if there is no selection. The property sheet also provides live editing of these values.

The Sidebar is also synchronized with the drawing area: selecting a design element in the sidebar tree view will select it in the drawing area and vice versa and the changes are propagated likewise in real-time.

Double-clicking an object type in the sidebar tree view will activate the creation of an instance of the selected type (this is similar to selecting the type from the toolbar). Double-clicking an object will open the property dialog for that object.

The usual element menus for both types and objects can be accessed from the tree view as well, providing such elementary operations like editing the type and its symbol (only in MetaEdit+ Workbench version of MetaEdit+) or fetching type info and editing properties, managing subgraphs and replacing for objects.

In MetaEdit+ Workbench, the object types in the tree view offer quick access to the modeling language definition: holding down the Shift key while double-clicking them will bring up the Symbol Editor for the selected type; holding down the Ctrl key will open the metamodeling tool for that type, e.g. the Object Tool.

The property sheet (Figure 4–26) provides a quick way to access and edit property values of the selection, and any subobjects in its properties. The property sheet always shows the property values of the most recently selected element of the graph or – if there is no selection – those of the graph itself.

The first text row of the property sheet displays the type of the current selection in red. Double-clicking it will open the property dialog for the currently shown element. In MetaEdit+ Workbench, it also offers quick access to the metamodel: Holding down Shift while double-clicking will open the Symbol Editor for the type while Ctrl+double-click will open the respective metamodeling tool. Clicking the right mouse button will bring up the element menu that provides these operations for editing the type and its symbol, and also for showing type info.

The other rows displayed in the property sheet represent individual properties and their values. The properties are organized in a tree in hierarchical fashion where the contents of complex properties are shown in their own branches (e.g. the elements of a collection property are displayed under the property itself). To select a property row, move the mouse cursor over it on the Property column and click the left mouse button.

The property sheet also provides editing features similar to those found in the property dialogs. Simple property values like strings, numbers, Booleans and lists can be edited by simply clicking them, or pressing F2. This will activate the respective in-place editing widget (plain input fields for strings and numbers and pull-down lists for Booleans and lists). If the property value is a text, a double click will open an editor for it. The values within more complex properties such as collections and non-property properties can be individually accessed and edited by opening the hierarchy.

The property sheet also provides some additional operations for managing complex properties directly. Double-clicking a collection property’s row will add a new element to the collection. Similarly, if there is no element attached to a non-property property, a double click will create and attach a new one. Please note that these newly created elements are ‘empty’, i.e. they have no values except the possible default ones. Double-clicking an existing element on a non-property property row, or pressing F2, will open the property dialog for that element. If the non-property is a graph, hold Ctrl key down while double-clicking to open that graph in an editor.

In addition to the direct creation and editing operations explained above, the property sheet also provides element menus for properties and their values. The menu actions include the usual Cut, Copy, Paste and Paste Special... operations for most elements, and such element-specific operations as adding, removing or moving elements in collections, or browsing and executing external elements where applicable.

The sidebar can be dragged to be wider or narrower, and its visibility can be toggled with the View | Sidebar menu item. The Options Tool Preference page also provides the following settings to alter the sidebar visibility, size and layout: