I am using anchored frames. But the problem is that they influence the line spacing. That is, if the frame is a little higher than the characters, the space to the line above increases. Is it possible in some way to avoid this influence on the line spacing?
An anchored frame within a text frame is always treated like a single character. So the behaviour of this "character" depends on the chosen type of text ruler, like it does with normal "characters", too.