[via Stefan Goßner]
Microsoft had to modify the behavior of ActiveX controls due to an existing patent from Eolas on this technology. See here for more details on this.
After the change ActiveX controls embedded in the html code of a web page have to be activated manually by a user - e.g. through a click on the ActiveX control. This can be very annoying for users.
This behavior change also affects the ActiveX control included in the MCMS HtmlPlaceholder editor component.
No, this won’t be an issue in the next version of MCMS, Web Content Management in MOSS, as there is no ActiveX client install requirement for authoring pages!