Sorry for the delayed response. Oh yeah. I see your point and you are indeed right. Unfortunately, I can not do that at the moment because I will need to change a lot of stuff and I am not the only one working on this project. But I will consider this on the next update of our application. For now, as Andre suggested, I inherit from QLineEdit my own class and I do some stylesheet "magic". It actually works fine. But yet, I find the QTreeWidget solution a better idea. I will give it a go soon!
Thank you all guys!
Cheers!