Steps to Reproduce

1. click each button on the page
2. check the position of a window

Current Result

only overlapped + top and popup+top is based on the top of the page, not the top of the visible area

Expected Result

be consistent

Debug Information

• top, position, 2 attributes with 4 modes (modal, highlighted, overlapped, popup), 8 cases in total. but only 2 cases are different which is quite special.
• since it changes specification a lot, fix it in the next major version