If this is true, then why the heck does it work fine if WB is not skinning it?
It works as it is designed....arguably badly...because it has not followed the 'rules' that other programs follow.
Microsoft likes to do things their way....it's their OS afterall. When 3rd party program writers follow their rules everyone is on the same page. Programs designed to alter/improve/append to the standard Windows GUI do so with total confidence they will do exactly that....but ONLY until some other third party program decides they think their way is better...and break those 'rules'.
It is the same reason you should never apply those 'patched' files to attempt to 'skin' Windows. You are breaking the 'rules' and thus are likely to break other programs as well.
Now Windowblinds skins just about every program exactly as intended. The only ones it will fail to apply correctly to [or appear to cause a bug] are those whose coders broke the rules that everyone else conforms to.
Yes, it is sometimes possible for Windowblinds to be 'adjusted' to compensate for others' bad practise... but that is actually not a Windowblinds 'bug' at all...