Open Source software is great. If there is something you don’t like, you can at least - try to change it. A lot of Open Source software out there is not primarily used by private people. There are many companies who provide professional services around Open Source software. Some of them try to enhance the appearance with custom User Interfaces, their company logo to fit their own Corporate Identity. There are several motivations, mostly they want to be distinguished on the marked or need some easy to maintain little customization which allows their sales guys easier to sell a project and not using the software from the community projects website. How hard could it be to make something pretty, right?
Open Source and User Experience Design
Open Source software is mostly driven by very enthusiastic technical people. These people build stunning flexible and valuable tools and allow every user and commercial entity to get involved adding value in freedom.
When it comes to User Experience Design, you will run inevitably into some problems. Every person has a different way using the application, some use the trackpad, mouse or want keyboard shortcuts. The number of clicks you need to get a task done, the distance of buttons you need to click for a certain task and of course there is - The Matter Of Taste™.
The colours picked from a palette, the minimal contrast ratio between colours to keep it readable and allowing you to identify things. There tons of forms with functionality like buttons, drop downs, input fields, icons and the probably the most underestimated thing - how things are named. This should be all homogenous through the application and there are different languages. Making a good job here is hard.
Theming as a misfeature
Just because they can, people make bad UX just worse by changing the major color to make it fit to their Corporate Identity and of course, there is always the questions: “Can we replace the product logo with our company logo?” How many people had the idea to show their company logo in applications like Excel, Outlook or when they login to Google Cloud Platform to manage their resources?
It is extremely hard to build a really good User Experience for complex applications. Do you seriously think having multiple bad User Interfaces makes the world for your users any better?
Web applications built in the early 2000 didn’t had that luxury. If you start building and Open Source tool you should seriously have a look at free and Open Source UI frameworks. That way you have at least a chance to get a working homogeneous look and feel.
Don’t worry, there are enough other places left you can fuck up your application with naming, wording, implementation of use cases and application workflows.
Just as an advise, if you can’t resist to provide your users a spot to show off themselves, allow custom background wallpaper images at the login screen. Once they logged in, it went away :)
Stop theming and build better UX for all of us.