Maybe Klaus can explore this. I also have experienced strange zorder behaviour when combobox is used. E.g. Cobobox when open even lower in zorder it is displayed over the overlay with higher zorder. No parenting or childs.
You can see at att image that only lower part of combobox is under the overlay. List is upper. Same for HTML5 and Flash version. Checked in memory zorders are checked and correct but display is not. All that with upper comment suggest something is fishy with the combobox


I have implemented workaround closing and opening the box when overlay is visible but this might be kind of blocker for people if it is realy some kind of inconsistency in combobox.

@Klaus: What to do with Flash version of combobox if we need some layer on top of it....as we can't change implementation inside SWF?

Last time I had a customer that wanted custom Flash SWF combobox colors. I spend hours downloading Adobe CC Flash, registering, to come to the code AS3 adapt it, publish and after several tests to confirm my new colors are ok.

Now I am more of the opinion and the feeling if this is kind of bug or incosnsitency that Klaus with next release publish new version with this z-index issue fixed.
Anyway thanks for discussion. It was productive.
Anton