Wicket 6.0.0 came with some nice improvements in the header contribution management.
With these improvements it is possible to put a specific header contribution at the top of all others by using PriorityHeaderItem, or to group several header contributions in a specific spot in the page body by using FilteredHeaderItem, but still it was quite hard to something simple like making sure that <meta charset=”utf-8”/> is always the very first item in the page <head>.
With WICKET-5531 (since Wicket 6.15.0) we added one more facility that should make header contributions management even more flexible.
By using markup like the one below in YourPage.html
all header contributions done by using IHeaderResponse in your Java code or the special wicket:head tag will be put between the <meta> and <script> elements, i.e. in the place of <wicket:header-items/>.
This way you can make sure that some header item is always before or after the header items managed by Wicket.
<wicket:header-items/> can be used only in the page’s <head> element and there could be at most one instance of it.