Removed articulation reappears on next articulation placement; disappears once deselected
When an articulation is removed (via use of select and then cut) it will reappear when a new articulation is placed.
When this "ghost" appears it is currently selected. Any action that deselects it causes it to disappear.
I have captured video of this happening and it can be viewed here:
As shown in the video, it is only the most-recently removed articulation that does this. And it does not have to be on the same note where the new articulation is placed.
Mac OSX 10.8.4, Muse v3 build 5702.