I think I found the problem,
When I uncheck "Allow this precompiled site to be updatable" while publishing the website, It means that I have puiblished the compiled codes for both pages and codebehinds. So all those compiler options now have been compiled. So changing the Debug to true or false, will not compile whole the website again. ( There is no code there to be compiled) and thus
#if DEBUG ...
does not work! (Because it is compiled with
Please let me know if you think something else.
Thank you guys again.