For uvision 5, when open multiple documents, one thing importan is that to identify which document you are working on. Current IDE applied different color for different tag for every document, and underline the name of the currently on working one.But the tag color is different from the work area background. My suggestion is that to switch the current tag color to the work area backgrod color, and make the tag bottom open to extend to the work area. This will be much easier for user to identify the current document. I have prepare an example picture. give me e-mail address then I will send the example.