Changing font size wit "AA" button doesn't work

[Guest]

One of our customers creates a ePub file of version 2.0 with TextMaker.

When trying to increase or decrease the font size with AA button at top right, it doesn't work with Adobe Digital Editions 4.0.3.

However there are no problems doing the same with Calibre.

We can reproduce this bug. And it happens even for files which does not have CSS styles and font formats.

(I removed it manually and added <h1></h1> to format the headings.)

Is this a known problem with the Adobe Digital Editions editor?

Or is it a problem with an incompatible ePub format?

[Guest]

Obviously the Adobe Digital Edition can't scale fonts with a size given in points.

I created a sample file and I replaced the font sizes with 1em. Now it works.