TCA is one of the more recent software systems that is based on Visual Basic programming. Source code is written in more than one programming language but predominant is VB6. The reason is quite simple. VB6 is close to pseudocode, offering the possibility to focus more on building the algorithms rather than on writing time-consuming code. Understanding the studied processes and creating the algorithms are the core of any scientific software system building activity. Writing the code is just the implementation phase that offers the possibility to verify the results and that should happen quickly. Otherwise, the research of the phenomenons would be dragged over a long period of time due to the implementation phase. In border sciences, such as colour science (which requests knowledge in the fields of chemistry, physics and mathematics), it is important to have more time to study and understand how to address the problems, in order to create viable algorithms, than to waste time on writing complicated computer language syntaxes. Large software programs that aim to solve a variety of problems are usually not written today in only one computer language. That is because some languages are better suited to some problems, and some are not. I started learning computer languages when Fortran 77 was leader and learned several computer languages since then. VB6 is not a strongly typed object-oriented programming language and that's why I'm not exclusively using this language but VB6 earned its place among the top computer languages for good reasons that should not be underestimated. Ultimately, it is software developers that make computers useful and Operating Systems attractive, and if there's a large number who say that VB6 should be supported, then Microsoft should continue to support it in its own interest.
A comment by Razvan Preda