# New Developer Feature - StyleTester

**URL:** <https://discourse.slicer.org/t/new-developer-feature-styletester/15509>\
**Category:** Development\
**Tags:** feature, gui\
**Created:** [January 13, 2021, 4:42pm UTC](https://discourse.slicer.org/t/new-developer-feature-styletester/15509 "2021-01-13T16:42:20Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Sam\_Horvath](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/sam_horvath/32/3092_2.png) [@Sam\_Horvath](https://discourse.slicer.org/u/Sam_Horvath)\
**Post date:** [January 13, 2021, 4:42pm UTC](https://discourse.slicer.org/t/new-developer-feature-styletester/15509/1 "2021-01-13T16:42:20Z")

</div>

We’ve added a new utility module to the SlicerSandbox extension, [StyleTester](https://github.com/PerkLab/SlicerSandbox/tree/master/StyleTester). StyleTester allows you to test modifying the appearance of the Slicer GUI using [Qt Style Sheets](https://doc.qt.io/qt-5/stylesheet.html). Qt Style Sheets provide an very powerful method for customizing every aspect of the appearance of a Qt-based application like Slicer.

QSS code can be entered into the editor, or loaded from / saved to .qss files. The module provides a set of example widgets that can be used to view effects of stylesheets on the most widely used objects. The StyleTester source code is also a good reference for reading and using stylesheets in custom code.

Example of applying a simple stylesheet to all of Slicer:

| Before Apply | After Apply |
| --- | --- |
| ![Screenshot 2021-01-13 09.44.04](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/8/5/859dd75fab8f8943658533db9241fc3321fa2982.png) | |

The StyleTester is available starting in today’s Preview build through the SandBox extension.

* * *

Sam