On A5W web pages you can select Insert Xbasic to open up a dialog to enter xbasic. When you do this instead of just adding the code to source, the code is encased under a clickable object labled [<%A5...%>]. You can easily open and copy-paste the contents of this object, but you cannot copy-paste the object itself.

When you try to paste it, some code is pasted, but not the code that was in the original object.

I would not think it is a bug, just a limitation.