Currently it is not possible to limit a dashboard box to certain pages.
If you happen to implement a box that only makes sense on certain pages, e.g. because it displays additional information (e.g. the "More Files" box in the Plugin-Store) you have to hard-code the box into the template, but that completely destroys a users ability to sort those boxes.
There, I propose to add the ability to limit dashboard boxes to certain pages. It could look like this in the dashboardBox.xml:
Where the item inside <scope> ... </scope> has to be a proper com.woltlab.wcf.user.dashboardContainer object type. Additionally, wildcards (*) should be allowed, e.g. <scope>com.hg-202.news.*</scope>.