When i have a large diagram, every time i use the reset zoom button, the diagram fit in the screen but ignores the tools panel in the process, ending up in the diagram being behind the tools panel.
I was able to reproduce the same issue on the Demo editor, as screenshot shows:
I believe that a quickly workaround would be change the transform matrix everytime i reset zoom to add an offset to the viewport, but i dont know if it’s even possible, once i tried a simple test changing the matrix values on HTML but seens that the view dont update when values are changed this way.