Diagram Editor

The diagram editor is an essential part of the diagramming and modeling tool. It provides tools and capabilities for quick and easy diagram creation.

What is Diagram Editor?

The diagram editor fills the major area of the main application window. The largest part of the editor represents the editor canvas that provides space for your visual creations. The diagramming tools are organized in the toolbox, which is docked on the left side of the editor canvas with the default settings. The tools are grouped into several groups by their usage. The Common group contains tools that are offered for all the diagram types. It is followed by other groups with diagram-specific tools.

Diagram Editor - diagram canvas and toolbox
Diagram Editor - diagram canvas and toolbox

Split Diagram Editor

The diagram editor can be split vertically into two independent views. This way you can compare two parts of large diagrams or edit the diagram simultaneously in two places. You can find the split button (small rectangle) above the vertical scrollbar. To split the diagram view, grab the button and move it down. The diagram editor gets divided into two independently scrollable panels.

The diagram editor split into two parts
The diagram editor split into two parts

Context Bar

The context bar is displayed near the selected element - usually, it is under the left bottom corner of the element. It shows the popular actions for the current selection.

Context Menus

You can show the context menu when you click using the right mouse button somewhere in the diagram editor. The menu offers specific options for the clicked context. It will show some actions if you click on a free space on the diagram canvas and other actions if you click on an element (e.g. class) or a field (e.g. class attribute).


You can navigate the diagram very easily. You even do not need to switch to the Panning tool (in the toolbox). Just press the right mouse button over a free space in the diagram canvas and move in any direction while still holding the pressed button.

Another quick option is to press and hold the Space button (the mouse cursor can be anywhere over the diagram editor even over elements) and move the mouse cursor over the diagram editor. The diagram canvas will scroll according to the cursor moves.

Diagram Editor Layout Helpers

The diagram editor provides various layout helpers. The elements snap to the borders of other nearby elements. The dragged or inserted element can be also aligned vertically or horizontally to the centerline of another element. The snaplines have different colors, so you can seed whether the element will be aligned to the centerline (purple line) or borderline (blue line).

The diagrams with uniform element sizes look better. Software Ideas Modeler suggests you existing popular width and heights for the edited element. The size can be snapped to recommended option during the element resizing or inserting.

You can suppress the snapping very quickly if it is not desired in the given situation. Just hold the ALT key and you can move and size the edited element without any restriction.

Another helper for diagram creation is the grid. You can turn on the grid and choose any spacing you need. All the diagram elements will be aligned to the specified grid.

Renaming in Diagram Editor

If you need to rename an element in the diagram editor, click or double-click (depending on your settings) on its name and then edit the name or enter a new one.

You can also select an element and press the F2 key to rename it.

Drag & Drop in Diagram Editor

Drag & drop action over the diagram editor can have various outputs depending on the used tool and cursor initial placement.

  • if the selection tool is active and you start dragging from an empty space in the diagram canvas, it will specify the selection bounds and select the containing or intersecting elements on the drop.
  • if the selection tool is active and you start dragging from an existing diagram element, it will move this element to a new position.
  • if an element tool is active and you drag anywhere over the diagram canvas (even over the other elements), the bounds of a new element are specified and the new element is inserted on the drop.

Right Drag & Drop in Diagram Editor

If you drag an element using the right mouse button, the diagram editor will show you more actions in a context menu when you drop the element into a new position. This way you can connect the dragged element with another new element by your choice, create a duplicate of the dragged element or copy some attributes (style, size) to another element if you drop the element over another diagram element. You can also swap the elements with each other this way.

Context menu for right-button drag&drop action
Context menu for right-button drag&drop action

Auto-Size Elements in Diagram Editor

You can resize an element to its best size very easily - just double-click its right-bottom sizing grip.

Diagram Editor Settings

The diagram editor can be adjusted according to your preferences. The Options dialog (File/Options) provides many settings that can modify the default behavior of the editor for renaming, moving, container handling, selection, and others. You can read more about diagram editor settings here.

New Comment