Gustaf,
I confess that I had missed the significance of the '-style plain' parameter. Since first working with CSS and xowiki, I had been using '-style none'.
{{available-includelets -id rhtest -decoration plain}}
provides:
<div id='rhtest' class='available-includelets'>
This means you could have multiple instances of an includelet on a single page and style them either consistently or uniquely.
That's really powerful. 😊
R.
