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Conceptual Model

The conceptual model is the most fundamental aspect of the interface, describing the relationship between the interface and the outside world. The purpose of the conceptual model is to draw on the user’s past experiences so they can readily understand basic operations and accurately predict functionality.

  • Real World, Vision

Task Flow

The task flow is concerned with the manner in which users’ complete specific operations with the system. In contrast to the conceptual model, the task flow is largely dependent on the product’s technical environment.

  • Core usability goals, Use cases / User requirements, Task aggregation
  • Personas, Scenarios, Usability criteria, Feature list

Organizational Model

The organizational model describes how the system’s content and functionality are ordered and categorized. Also known as the information architecture, the organizational model encompasses both the classification scheme as well as the model of association, hierarchy versus index for example.


All HIGs assume that the controls referenced in the following "Implementation" sections are used. Therefore they only contain guidelines for aspects which can be changed by the developer, to keep them as concise as possible. If you feel your application needs something which the referenced standard KDE or Qt widget does not provide, do not create you own custom replacement, because it might violate best practice which is implemented in the standard widget. Instead, ask the KDE HIG team for advice on how to solve your specific problem.

Viewing and Navigation

The Viewing and Navigation layer encompasses the wide variety of behaviors and operations that allow users to navigate the interface and effect its presentation.

General navigation

Access functions


  • Group box, Panel
  • Splitter

Complex views

  • Use a List View to show some items out of one category.
  • Tree view
  • Grids
  • If you really need to create your own widget follow the guidelines for custom controls.

Editing and Manipulation

The Editing and Manipulation layer contains the behaviors that result in permanent changes to user’s stored information. … Behaviors in this layer can often be recognized by the following traits: they result in permanent, stored changes; they require an implicit or explicit save operation; and they typically require validation of the input data.


  • Use a radio button for 1 of a few n selections.
  • Use one or more check boxes for clear options or n of a few m selections.
  • Use a list view for one or a few n of some m selections.
  • Use a drop-down list for 1 of some n selection and a combo box if users should be able to add items.
  • Use the dual list pattern for n of m selections.

Unconstrained input

  • To enter one line of text use a line edit and for multiple lines of texts a text edit.
  • Consider to provide inline editing with complex views.

Constrained input

  • Use a Spin Box for numerical input within a range and with fix steps.
  • Use a Slider for arbitrary changes within a defined range.
  • (Under construction): Numeric input with both large changes and precise control: Slider and Spin Box
  • Use Date and Time Pickers for formatted input of datum, time of day, or periods etc.

User Assistance

Interface elements that inform users of the application’s activity and status, as well as elements dedicated to user education, are all contained in the User Assistance layer. This includes online help, error alerts, and status alerts.

User-driven information

  • Provide tool-tips for user driven information.

System triggered notification

Disruptive messages

  • Show a modal message dialog if the processing has reached an unexpected condition that needs interaction.

Help system

  • Support the user by an elaborated interface or per help system.



The various design decisions governing the placement and ordering of onscreen elements are expressed in the Layout layer. In addition to providing an ordered visual flow, the Layout layer also supports the Behavior tier by arranging elements in a manner that helps communicate behavior, importance, and usage.

  • Resizing
  • Default and minimal size
  • Spacing
  • Alignment & Placement
  • Do not use color as primary method of communication.
  • Icons


Like many forms of visual design, the Style layer is concerned with emotion, tone, and visual vocabulary. Because it is the most visible and concrete aspect of an interface, it typically accounts for people’s first impression of a product. Paradoxically however, the ultimate effect of style on overall usability or user satisfaction is minimal.


Contained within the Text layer are all the written, language-based elements of the interface. This includes the labels used to represent the organizational model, the names of the input and navigational controls contained in the Viewing and Navigation layer, and the alert messages and help text used by the User Assistance layer.

See also:


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A guide to the guide can be found at the about page.

Our Human Interface Guidelines are a work in progress and we need your help. Visit the Contributing page to report problems or get involved.














Legacy Stuff

List Views

Please add any guidelines questions or requests to the HIG Questions page.

Also see the Season of Usability HIG & Design Patterns Workspace.

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