listbox (autopaging) listitem height incorrect between iceblue/iceblue_c

Steps to Reproduce

copied from github https://github.com/zkoss/zkThemeTemplate/issues/16

check out the fiddle:
https://zkfiddle.org/sample/1bt07rq/1-listbox-with-autopaging
if you use iceblue you can see that the listitem is not heigh enough. The combobox gets cut.
When you use iceblue compact you see that the listitem height obviously is too heigh...

the problem seems to be:
.z-listbox-autopaging .z-listcell-content

This is the same in both layouts.
if you remove that height style, the height is the expected size

Current Result

iceblue (cut off comboboxes)

iceblue_c (wasted space below comboboxes)

Expected Result

specify default autopaging row height suitable to the current theme (default and compact)

similar to breeze theme where the default autopaging height fits by default

Debug Information

from the github issue:

If you use grid instead of listbox, the styling is as expected.

Workaround

specify a different height via css