It seems, that even with filtering, my Habpanel still loads all items.
When comparing
http://OH-IP:8080/rest/items-filtered
with
http://OH-IP:8080/rest/items?recursive=true
it’s a 1/6 th of the full items list.
The Webbrowser Debug still mentiones “items” are loaded and it takes 6 seconds.
In the details of the items analysis I see items, which are not in the group Group_HabPanel_Dashboard
Do I need to activate this somewhere?
(I just copied the two addons in the addons folder and don’t use the officcial habpanel of the 2.5 stable release)
EDIT:
Damn, I am an idiot. I called the “static” webside.
After using
http://OH-IP:8080/habpanel/index.html#/view/Home
it mentiones items-fltered
However, it’s still slow.
Which brings me to another feature request 
2 (or more) independent filter groups (one for my phone, which is fast enough), one for the wall tablet (which is slow and just requires a few items)