It is extremely rare that you actually need to block the UI. Most uses of modals would be better served with local notification that respects fitt's law. An exa

It is extremely rare that you actually need to block the UI. Most uses of modals would be better served with local notification that respects fitt's law. An example would be popping up a "confirmation tooltip" adjacent to a delete button that was just pressed. The subsequent required mouse movement will be a short travel away. A modal in the middle of the screen moves the locus of focus, is jarring and blocks the UI. Simply put, blocking the UI is hostile.