HABPanel Template Widget, nothing works

Have been doing some simple HABPanel stuff just to get started a bit, but wanted to try te Template Widget out.
I thought the examples I’ve seen should just be pasted into the widgets “edit window”, but I cant get anything to evaluate.
The simplest examples I’ve seen, such as

{{ 5+5 }}


<h4>Hello world!</h4>
It's {{itemValue('astro_sun_local_season_name') | lowercase}}
and the sunrise is at {{itemValue('astro_sun_local_rise_start') | date:'HH:mm'}}

is presented just as the text shows here, so nothin within the curly braces evaluates, as I thought it would.
So, clearly I’m missing something fundamental here.
Anyone that can help me in the right direction?

Running OpenHAB 2.5.12 by the way.


Never mind…
I must have gotten some junk in there, because when starting fresh again I get values.