The patch for bug 339041 allowed XPConnect global objects to have JSCLASS_GLOBAL_FLAGS. I'm extremely unhappy with that patch, however. There are cases that it doesn't cover (where it's possible for us to create a class which has the wrong flags) and it's extremely invasive. I still think that we should add an nsIXPCScriptable flag for this purpose, since that's the only information available to XPCNativeScriptableShared::PopulateClass, which is really where we need the info to be.

Per policy at https://wiki.mozilla.org/Bug_Triage/Projects/Bug_Handling/Bug_Husbandry#Inactive_Bugs. If this bug is not an enhancement request or a bug not present in a supported release of Firefox, then it may be reopened.