From KDE Community Wiki

We can distinguish three kinds of inline messages:

  1. Positive or negative feedback
  2. Opportunistic interaction (example: Firefox "remember password" bar)
  3. Find/replace panels

Feedback and opportunistic interactions are implemented by KMessageWidget.

Find/replace like panels are implemented by KDialogWidget.


Negative feedback

The KMessageWidget should be used as a secondary indicator of failure: the first indicator is for instance that the action the user expected to happen did not happen.

Example: User fills a form, clicks "Submit".

  • Expected feedback: form closes
  • First indicator of failure: form stays there
  • Second indicator of failure: a KMessageWidget appears on top of the form, explaining the error condition

When used to provide negative feedback, KMessageWidget should be placed close to its context. In the case of a form, it should appear on top of the form entries.

KMessageWidget should get inserted in the existing layout. Space should not be reserved for it, otherwise it becomes "dead space", ignored by the user. KMessageWidget should also not appear as an overlay to prevent blocking access to elements the user needs to interact with to fix the failure.

Positive feedback

KMessageWidget can be used for positive feedback but it shouldn't be overused. It is often enough to provide feedback by simply showing the results of an action.

Examples of acceptable uses:

  • Confirm success of "critical" transactions
  • Indicate completion of background tasks

Example of wrong uses:

  • Indicate successful saving of a file
  • Indicate a file has been successfully removed

Opportunistic interaction

Opportunistic interaction is the situation where the application suggests to the user an action he could be interested in perform, either based on an action the user just triggered or an event which the application noticed.

Example use cases:

  • A browser can propose remembering a recently entered password
  • A music collection can propose ripping a CD which just got inserted
  • A chat application may notify the user a "special friend" just connected


The KMessageWidget should provide two possible shapes: line and rectangle.


Example of layout for a negative feedback KMessageWidget:

| {X} Wrong username or password               |

{X} stands for the 'dialog-error' icon

Example of layout for an opportunistic interaction KMessageWidget:

| {i} Remember password for site example.com? (Remember) (Do not remember) (X) |

The widget height is always the height of one line of text plus margins. If text is too long, it is cropped like this:

| {i} Remember password for... _more_ (Remember) (Do not remember) (X) |

Clicking on _more_ expands the widget to multiple lines:

| {i} Remember password for site      (Remember) (Do not remember) (X) |
|     example.com?                                                     |

Note: One should try to ensure the beginning of the message text makes it possible for the regular user to understand the message without clicking on the _more_ link. So avoid generic introductions like "Do you want FooApp to...".


Example usage: showing feedback at the bottom of a sidebar.

| {i} Do you want to (X) |
|     rip this CD?       |
|                        |
|               (Rip CD) |

Queuing: KMessageWidgets should not stack on each others. Assuming KMessageWidget A is visible, if KMessageWidget B is created, it should wait until A has been visible for at least 3 seconds and replace it.

Widget API

  • Properties
    • tone (negative, neutral, positive)
    • text
    • shape (line, rectangle)
    • showCloseButton
  • Methods
    • addAction(QAction*)
    • setMainWidget() low-level method to replace the existing text + buttons layout with a custom widget. Setting text and adding actions with addAction() should be preferred whenever possible.


  • Initiated and ended by the user
  • Primary task but not the primary function of the interface
  • Examples:
    • Find/replace
    • Spellchecking
    • Filtering


Content of the widget is on the left, close button is on its right, naturally appearing when user finishes reading the line.

| Find: [_______] (Done)                                           |
|    Find: [_______] (Next   ) (Previous   ) (Done)                |
| Replace: [_______] (Replace) (Replace All)                       |

The widget can optionally provide two different content, one thin and one taller. It will then show a collapse/expand button, like this:

| (+) Find: [_______] (Done)                                       |
| (-)    Find: [_______] (Next   ) (Previous   ) (Done)            |
|     Replace: [_______] (Replace) (Replace All)                   |

To be refined

  • Integration with KNotification?
  • Definition of a container to implement queuing rules?