Visual Foo, the project that eventually led to Delphi, had one directive; create a development environment more visual than Visual Basic. We took that mandate very seriously. During the height of the project we produced some lovely prototypes that resembled the soon to be discontinued Yahoo Pipes or Microsofts long since discontinued Popfly.
What we learned, and I can only assume that Yahoo and Microsoft learned much later, was that such approaches are not better, they are just different. Making something more visual doesnt, by itself, make it better it just makes it more visual.
I put Visual Foo and projects like it on a list of mistakes that every generation will make. I am convinced this model will come back with as much or more fanfare than Pipes and Popfly did and will eventually die just as they did. There are some mistakes that are so appealing they will be made over and over again.
Delphi was a step back from the radical approaches that we experimented with in Visual Foo project. It competed directly with Visual Basic instead of trying to be more visual than Visual Basic. We believed Delphi brought a better compiler, a better language, and a system that was much easier to extend.
I have since developed much more respect for the design of the Visual Basic language than I had at the time. It is still not among my favorite languages but I no longer run away screaming.
When you look closely at Visual Basic you realize that it is neither Visual nor BASIC. It is not really BASIC; it is a long, long way from Dartmouth BASIC or even Microsoft BASIC. It shared some of the characteristics of BASIC and kept some of the syntax but a Visual Basic program looks much different than one in its older cousins. It also isnt Visual. The only visual part of Visual Basic is that it has a form designer. The Visual Basic form designer appeals more to WYSIWYG than visual programming. All the actual programming is done in a text editor, not the form designer. Delphi is the same.
One of the things that made Delphis model easier was that you didnt have to visualize in your head where a thing like the file open dialog was, you could point to it, It is right there next to the button that opens it. You can move it around; reach out and touch it so to speak. I never expect this to gain coinage, but this is why I sometimes refer to Delphis programming model as tactile programming, not visual programming. Simplicity was helped more by the illusion that you could touch the component, moving it where you want it, not just that you could see it. To keep this illusion it should act as close to a physical object as was reasonable. It needed to feel like you could pick it up.
It is this concept that helps explains why I never created a gutter for non-visual components. Any restrictions on a components movement breaks the illusion. This also explains why the Data Module looks and acts like a form; it helps reinforce the illusion. If the component can only appear off screen or in a restricted area, it no longer feels like a physical thing, the illusion breaks down. Even though non-visual components can get in the way of the forms layout, I felt maintaining the illusion was more important than the irritation the real estate they consume causes.
Making something visual helps simplicity when it reinforces the conceptual module of the underlying system. It hurts when it tries to visualize something better left in code.