The source of memory leaks is always hard to pinpoint.
In this case I have a plugin which has no memory leaks in R16 and above. Once migrated to the R20 SDK it reveals the following:
Memory Leaks Detected: p:\c4d_perforce_work\release\20.0\modules\xtensions\source\manager\datadescriptioneditor\dde_dialog.cpp (5333): Memory leak of 80 bytes () at 0000002476158C40 1 blocks not freed
Went a little further, and started the Visual Studio debugging AFTER having removed the xdl64 file in the plugin folder ...
Meaning I am debugging Cinema 4D without my plugin loaded, nor even being present.
Close Cinema 4D and still get the exact same memory leak.
Even went as far as removing ALL plugins from the system -> still same memory leak.
I think this one is for you guys to fix ;-)