Photoshop CS6 64bit WIndows 7 64 Bit.
Using pen tool to create a mask.
After de-selection of path (using pointer tool, paintbrush or anything else) the vector line including the control points does not disappear as normal.
Deleting the layer removes it, but changing the visibility of the layer does not have any effect - it simply stays onscreen.
Radeon HD4850 card with latest drivers.