When I create a new "Codeblock" Makro i will copy my codeblock in the codeblock-content.
In Confluence 7.5.2 everything works fine - leadings blanks/tabs where inserted.
In Confluence 7.7.2 and 7.7.3 the leadgins blanks/tabs will be removed. The code is "left-aligned".
Because of this, we didn't update to 7.7.2.