This seems to me like an elementary question, but I don't recall having such an issue when I used Flash in the past, but if I recall correctly, shape tween was an element to this also.
I have a line, it rotates 270 CCW on a motion tween like a clock hand, but when I elongate the line in the final keyframe, it ends up increasing the line thickness. Is it only possible to avoid this by converting all lines to fills only?