XWiki#getCurrentContentSyntaxId() may return wrong value inside wiki macros

When setting a default syntax other than XWiki 2.1, macros such as document tree cease to render.

Setting it either through xwiki.pproperties

#-# [Since 1.8RC2]
#-# Specifies the default syntax to use when creating new documents.
#-# Default value is xwiki/2.1.
core.defaultDocumentSyntax = markdown/1.1

or through Admin > XWiki.XWikiPreferences will cause {{documentTree/}} to render as:

(% class='xtree ' data-responsive="true" data-url='/xwiki/bin/get/XWiki/DocumentTree?outputSyntax=plain&' data-dragAndDrop='false' data-contextMenu='false' data-icons='true' data-edges='true' data-checkboxes='false' data-openTo='' data-finder='false' %)((()))

However, removing the default syntax and just setting the new page syntax to markdown/1.1 will not break the macro.

This has been discussed in the users mailing list