Setup like this:
1. Type a one-liner in a text frame
2. Set top margin inset to 2 mm
3. Set height of text frame to 1,9 mm - overflow visible or not makes no difference Correction: Overflow has to be visible
Result 1: No overflow warning
4. Click the top or bottom centered handle of text frame. Normally used to fit the frame to adapt to the height of the text
Result 2: The text frame jumps to the upper left corner of the page, every single character (except spaces) is aligned vertically, all values for this text frame in the Transform panel have the value 0 (changing height or width do not change anything)
jumping-frame.afpub