You cannot resize a box collider when you have to inspectors open at the same time. Happens probably for reflection probe as well (though is untested).

2) How can we reproduce it using the example you attached

1 Create new project
2 Create empty object and add BoxCollider to it
3 Open up two inspector tabs which are visible at the same time
4 Select this object with boxCollider in Hierarchy

5 Click "Edit Collider"-button in first Inspector tab(which was opened first), notice that you CAN see the draggable rectangles and it works as expected

5 Click "Edit Collider"-button in second Inspector tab(which was opened second), notice that you DON'T see the draggable rectangles and you CAN'T edit collider - what is not expected

Expected behavior: Both Inspector tabs should be synchronized