Text animations do not maintain font size

[gfhcs]

In my presentations I often have bullet lists, i.e. a single text box that contains several lines of text. There are animations that allow me to reveal the lines one after another. ExpandAnimations does take care of this: It basically creates one slide per line, in which the text box contains only the lines that have been revealed so far.
The problem is: Since the text box automatically adjusts the font size of its content, this leads to the very first line appearing in a large font size. When the second line is revealed, the font size of the first line decreases, because now that the text box should contain two lines it adjusts the font size. A further decrease (this time for the first two lines) happens when the third line is revealed, and so on.

Workaround: I will now manually try to turn off this "automatic font size" and hope that this helps. But I think ExpandAnimations should do this for me.