Can I make my gui look like MATLAB's diagram viewer?

MATLAB's diagram viewer is of course just an example. Currently I'm programmatically writing my gui with a uifigure, I assume that's similar to app designer's style. I strongly dislike how slow it is and it's also looking amateuristically.

I found the ToolGroup object on Undocument Matlab and I've explored it a bit, but there's not much more info about it. Does anyone know where I can find more about it? Or could anyone tell me how the main panel below the toolstrip can be populated? Do I place a figure there and populate the figure with uicontrols? Or is there another technique?