Have a look at this figure below, which is a Quick Book Enterprise Solution 2014
Judging by its interface (not its DLL), I don't think you can easily guess with what platform/language does the above application was created. Qt? .NET? Java? It has its own border, custom menu, ... etc. In a simple wording, "it has totally customized UI that make it stand from the rest".
What do we need to be able to create this kind of application with fully customized UI? And what if I add cross platform aspect in this application? Different customized widgets in different OSes... but maintaining the same level of UI appearance...
I have previous experience with Qt, .. but I am not sure Qt can do this.. or is it?