KWin allows the end-user to define rules to alter the behavior of an application's windows.
For example, when an application is started, it can be forced to always run on Virtual Desktop #2. Or a defect in an application can be worked-around by using a rule to, say, always force the window on top of all others.
This page will define the different settings and the attributes. For the impatient folks, working examples will be listed. Whenever possible, screen shots will be used to show example settings.
A collection of examples is provided to convey the power of KWin window rules.
KWin Rule Editor
Invoking the Editor
There are several ways one can invoke the Rules editor. Below are a couple:
- Right-click on the title-bar of any window, choose and in the Configure window, select or
The editor is composed of four tabs:
As the name implies,is used to specify criteria to match one or more windows. The other three tabs are used to alter the characteristics of the matching windows.
When an application starts (or the rules are modified), KWin evaluates the rules from the top of the list until either a matching rule is found or the list is exhausted. If a rule matches, the attributes set in the rule are applied to the window and the window is displayed.
Thetab provides a series of matching-criteria fields used to identify application windows:
- match this window and all its children windows.
- - restrict the match to the function of the window (e.g. a main window, a chat window, etc.)
- - restrict the match to the type of window: Normal Window, Dialog Window, etc.
- - restrict the match to the title of the window.
- - restrict the match to the host name associated with the window.
For each field, the following operators can be applied against the field value:
- - case insensitive.
- - Qt's regular expressions are implemented. For additional information, web search qt regex nokia.
Detect Window Properties
Thefunction simplifies the process of entering the matching-criteria.
- For the application you'd like to create a rule, start the application.
- Next, in the tab, set the number of seconds of delay before the function starts. The default is zero seconds.
- Click on and
- When the mouse-cursor turns to cross-hairs, place it inside the application window and left-click.
- A new window is presented with information about the selected window:
- Machine (hostname)
Click thebutton to back-fill the criteria.
By using a combination of the information, you can tailor whether a rule applies to an entire application (by Class) or a to a specific window Type within the Class - say a Toolbar.
The attributes which can be set are grouped in three tabs:
Each attribute has additional settings which determine when they're applied and depending on the attribute, there may be an additional argument.
Each attribute minimally accepts one of the following parameters. Additional, attribute-specific arguments are listed within each attribute definition.
- Do Not Affect
- Unset the attribute.
- Apply Initially
- Start the window with the attribute and allow it to be changed at run-time.
- Use the attribute setting as defined in the rule and if changed at run-time, save and use the new value instead.
- The setting cannot be changed at run-time.
- Apply Now, Force Temporarily
- Apply/Force the setting once and unset the attribute.
Apply Now allows the attribute to be changed at run-time. Use Force Temporarily to not allow the attribute to be changed.
Size & Position
- Position the window's upper left corner at the specified x,y coordinate.
- The width and height of the window.
- Maximized horizontally, Maximized vertically, Fullscreen
- These attributes are used to toggle the maximum horizontal/minimum horizontal/full-screen window attribute.
- Place the window on the specified (Virtual) Desktop. Use All Desktops to place the window on all Virtual Desktops.
- Minimized, Shaded
- Toggle the Minimize and Shading window attribute. For example, a window can be started Minimized or if it is started Minimized, it can be forced to not.
- Initial placement
- Override the global window placement strategy with one of the following:
- Default - use the global window placement strategy.
- No Placement - top-left corner.
- Smart - place where no other window exists.
- Maximizing - start the window maximized.
- Top-Left Corner
- Under Mouse
- On Main Window - restrict placement of a child window to the boundaries of the parent window.
- Ignore requested geometry
- Toggle whether to accept or ignore the window's requested geometry and ignore the global placement strategy.
- Minimum size, Maximum size
- The minimum and maximum size allowed for the window.
- Obey geometry restrictions
- Toggle whether to adhere to the window's requested aspect ratio.
Arrangement & Access
- Keep above, Keep below
- Toggle whether to keep the window above/below all others.
- Autogroup with identical
- Toggle the grouping (commonly known as tabbing) of windows.
- Autogroup in foreground
- Toggle whether to make the window active when it is added to the group.
- Autogroup by ID
- Create a group via a user-defined ID. More than one rule can share the same ID to allow for seemingly unrelated windows to be grouped.
- Override the default window behavior to either Tiled or Floating.
- Skip taskbar
- Toggle whether to display the window in the taskbar.
- Skip pager
- Toggle whether to display the window in the virtual desktop list.
- Skip switcher
- Toggle whether to display the window in the ALT+TAB list.
- Assign a shortcut to the window. When Edit... is clicked, additional instructions are presented.
Appearance & Fixes
- No titlebar and frame
- Toggle whether to display the titlebar and frame.
- Active/Inactive opacity
- When the window is active/inactive, set its opacity to the percentage specified.
- Deprecated as of >4.8
- Focus stealing prevention
- When a window wants focus, control on a scale (from None to Extreme) whether to honor the focus request and place the window on top above all other windows and give it focus, or ignore its request (potentially leaving the window behind other windows).
- None - Always grant focus to the window.
- Extreme - The window's focus request is denied. Focus is only granted by mousing to the window.
- Accept focus
- Toggle whether the window accepts keyboard input. Make the window read-only.
- Ignore global shortcuts
- Toggle whether to ignore global shortcuts while the window is active.
- Toggle whether to display the Close button on the title bar.
- Window type
- Change the window to another type and inherit the characteristics of that window:
- Normal Window
- Dialog Window
- Utility Window
- Dock (panel)
- Torn-Off Menu
- Splash Screen
- Standalone Menubar
- Block compositing
- Toggle whether to disable compositing while the window exists. If compositing is enabled and the rule specifies to disable compositing, once the window exists, compositing will be re-activated.