Preview Content of Model Components

Content preview displays a representation of the contents of a hierarchical model element, such as a subsystem, on the block. Content preview helps you to recognize the contents of the hierarchical element without navigating the hierarchy. Content preview shows blocks, signals, signal and block labels, and sample time color coding. It also shows signal highlighting and Stateflow® animation.


For Model blocks, content preview appears only when the model is open.

By default, new hierarchical elements show content preview. You can change the default using the Simulink® preference, Content preview displays for new hierarchical elements. Existing elements show content preview only if you enable preview for that element.

Content preview settings apply across Simulink sessions. Select the elements that you want to enable or disable content preview for, and then on the Format tab, click Content Preview.

The figure shows the Throttle & Manifold subsystem with content preview enabled.

Simulink scales the content preview to fit the size of the block. To improve the readability of the content preview, you can zoom or resize the block.

Elements that show content preview include:

  • Subsystem blocks

    Only masked subsystems whose Icon transparency property is set to Transparent and do not have an image show content preview.

  • Model blocks, for referenced models

  • Stateflow charts, subcharts, and graphical functions

Content preview does not appear for:

  • Hierarchical block icons when they are smaller than their default size in the Library Browser

  • Subsystem blocks when they have the Read/Write permissions block parameter set to NoReadOrWrite.

  • Protected Model blocks

  • Model blocks whose referenced models are not loaded

  • Models that have the classic diagram theme enabled in Simulink Editor preferences.


A slight delay can occur in drawing models that contain many hierarchical items that enable content preview if those items contain many blocks.

See Also