If you enter rate and time, it computes distance. If you change either rate or time, it recomputes distance. If you change distance, it recomputes whatever you entered earliest. Since rate is least recent, it will be computed from time and distance. The colors will change to reflect this.
Some web pages have multiple models.
You can change these in subsequent models, but the change will not ripple back up the panel to prior models. Some models are fairly complex, and have several variables with complex relationships. An example is the air coil design. A typical scenario for coil design proceeds as follows. If using insulated wire, wrap a ruler, measure and enter turns per inch.