Thanks guys, I've already been comparing source code my main question is about the software and techniques people use for that specific file bitcoingui.cpp.
Qt creator doesn't open a graphic preview where you can drag and drop the elements with it so I want to know how people are manipulating the layout in this file. Is there a way to do it graphically in Qt creator or is it done purely in code with people envisioning the changes mentally and then compiling periodically to check them? That seems a really inefficient way to program a layout but I am new so what do I know. Thanks