KDDockWidgets API Documentation  1.3

KDDockWidgets is a Qt dock widget library written by KDAB, suitable for replacing QDockWidget and implementing advanced functionalities missing in Qt.

Although KDDockWidgets is ready to be used out of the box, it can also be seen as a framework to allow building very tailored custom docking systems. It tries to expose every internal widget and every knob for the app developer to tune.


Throughout the years KDAB contributed and funded bug fixes and features to QDockWidget. Sadly, this was very painful. Each bug fix or feature took many days of implementation, and an equal number of days just to fix dozens of regressions.

QDockWidget mixes GUI code with logic with state, making it very hard to move forward with new features. Furthermore, our customers were getting more creative with their requests, so it was clear we needed a better docking framework.

You will find more information in these places:

We also have an in browser demo. Note however that this demo isn't fully featured, as it's running on Qt for WebAssembly.


  • Provide advanced docking that QDockWidget doesn't support
    • Native window resize on Windows (allowing for Aero-snap even with custom title bar decorations)
    • Arrow drop indicators for great drop precision
    • Allow for totally different, user provided, drop indicator types
    • Nesting dock widgets in a floating window and docking that group back to main window
    • Docking to any main window, not only to the parent main window
    • Docking to center of main window, or simply removing the concept of "central widget"
    • Main window supporting detachable tabs in center widget
    • Detaching arbitrary tabs from a tab bar into a dock area
    • Supporting more than 1 main window
    • Support for affinities, making some dock widgets only dockable on certain main windows
    • Allow to hide TitleBar and just show tabs. Allows dragging via the tab bar.
    • Exposing inner helper widgets so the user can customize them or provide his own
      • Customize tab widgets
      • Customize title bars
      • Customize window frames
      • Custom widget separators
  • Cross-platform (macOS, Linux, Windows, WebAssembly, Wayland, X11/XCB, EGLFS are working) See README-Wayland.md and README-WASM.md for platform specific information.
  • Layouting engine honouring min/max size constraints and some size policies
  • PySide2 bindings
  • Clean codebase
    • Not mixing GUI with state with logic with animations
    • Great test coverage, even the GUI and DnD operations are tested. 200 tests currently.
    • Fuzzer for doing random testing and finding bugs
  • Lazy separator resize
  • Reordering tabs with mouse
  • Partial layout save/restore, affecting only a chosen sub-set
  • Double click on title bar to maximize
  • Double click on separator to distribute equally
  • Show close button on tabs
  • Allow to make a dock widget non-closable and/or non-dockable
  • Optional minimize and maximize button on the title bar
  • FloatingWindows can be utility windows or full native

Screen capture

Screen capture


  • QtQuick support

Trying out the examples

A full demo that showcases most of the features lives in examples/dockwidgets.

A simpler example can be found in examples/minimal, which might be more indicated to learn the API, as it's less overwhelming than the full demo.

Open a terminal capable of building Qt5 applications. Make sure you have cmake, ninja, compiler, Qt, etc in PATH.

Adapt the instructions to suit your cmake generator and operating system. Build and install the KDDockWidgets framework:

$ cmake -G Ninja -DCMAKE_INSTALL_PREFIX=/path/where/to/install ../path/to/kddockwidgets
$ cmake --build .
$ cmake --build . --target install

Now build and run the example:

$ cd path/to/kddockwidgets/examples/dockwidgets/
$ cmake -G Ninja -DCMAKE_PREFIX_PATH=/path/where/to/install
$ cmake --build .
$ ./kddockwidgets_example

The installation directory defaults to c:\KDAB\KDDockWidgets-<version> on Windows and /usr/local/KDAB/KDDockWidgets-<version> on non-Windows.

You can change the installation location by passing the option -DCMAKE_INSTALL_PREFIX=/install/path to cmake.


From your CMake project, add

find_package(KDDockWidgets CONFIG)

and link to the imported target KDAB::kddockwidgets. That's all you need to do (the imported target also brings in the include directories)

You may also need to modify the CMAKE_PREFIX_PATH environment variable depending on where you installed KDDockWidgets.

Python Bindings

Please refer to README-bindings.md.


New features go to master while the stable branch only accepts non-intrusive bug fixes.

We'll try to remain source-compatible across versions. API will get a deprecation notice before being removed in the next version. Note that this source-compatibility effort is only for the public API. Private API (headers ending in _p.h) might change so you shouldn't depend on them. Private API is only exposed so more advanced users can override, for example paintEvent(), and not so they can change internal business logic.

We don't promise or test binary compatibility. It's advised that you recompile your application whenever updating KDDW.

Supported Qt versions and toolchains

KDDockWidgets requires Qt >= 5.9 (or >=5.12 if Python bindings are enabled). The QtQuick support will require Qt >= 5.15. Qt 6 is supported.

Regarding compilers, whatever toolchain is able to build Qt 5.9 should also be fine. Note however that MSVC 2013 isn't supported anymore due to compiler crashes.


KDDockWidgets is (C) 2018-2021, Klarälvdalens Datakonsult AB, and is licensed according to the terms of the GPL 2.0 or GPL 3.0.

Contact KDAB at info@.nosp@m.kdab.nosp@m..com to inquire about commercial licensing.

Get Involved

Please submit your issue reports to our GitHub space at https://github.com/KDAB/KDDockWidgets

When reporting bugs please make it easy for the maintainer to reproduce it. Use examples/minimal/ or examples/dockwidgets/ for reproducing the problem. If you did modifications to the example in order to reproduce then please attach the patch and not a picture of your changes. You can get a patch by doing git diff > repro.diff at the repo root.

Also state which KDDW sha1, branch or version you're using, and which operating system.

KDAB will happily accept external contributions; however, all contributions require a signed Copyright Assignment Agreement.

This is needed so we can continue to dual-license it.

Contact info@.nosp@m.kdab.nosp@m..com for more information.

Thanks to our contributors.

About KDAB

KDDockWidgets is supported and maintained by Klarälvdalens Datakonsult AB (KDAB).

The KDAB Group is the global No.1 software consultancy for Qt, C++ and OpenGL applications across desktop, embedded and mobile platforms.

The KDAB Group provides consulting and mentoring for developing Qt applications from scratch and in porting from all popular and legacy frameworks to Qt. We continue to help develop parts of Qt and are one of the major contributors to the Qt Project. We can give advanced or standard trainings anywhere around the globe on Qt as well as C++, OpenGL, 3D and more.

Please visit https://www.kdab.com to meet the people who write code like this.

Stay up-to-date with KDAB product announcements:

Klarälvdalens Datakonsult AB (KDAB)
"The Qt, C++ and OpenGL Experts"
Advanced Dock Widget Framework for Qt