I made a form with 2 different tabpanels on it…did not change their name propertie so both tabs were “tabs_70”… On the rich-client displayed fine but on web-client they overlapped (they seems to be sharing the same anchor position), I just changed the name of one of them and anything worked. (btw… maybe could be a good idea to have developer assign a progressive name when placing multiple tabpanels on a form…)
About tabpanel actual limitations:
tabs hide seems to be missing, only top tabs location seems to be working.
On webclient I cannot change tabs with method: elements.tab_tab.tabIndex = xx; this is an actual limitation (Not yet functional: Read-only/editable properties and JavaScript manipulation of form elements).