Wiki Macros which require programming rights don't work in panels

Although wiki macros which use protected Api work in pages authored by users which don't have programming rights, they don't work in the panels.
This issue is related to issue XWIKI-6823 (see comment of XWIKI-6823) but it's different in the fact that XWIKI-6823 refers to all code using programming rights (which would require programming rights), this issue refers to wiki macros which normally work without requiring programming rights for the document in which they're used.

To reproduce, import the attached .xar, which contains a macro (prmacro) and a panel (PRPanel) and configure this panel to be used in a space somewhere. It will display

false
$xcontext.context.class

while using the macro in a document authored by a user which only has edit rights (no programming), it will display:

true
class com.xpn.xwiki.XWikiContext

I would expect the macro to work "everywhere".