Anyone else run into this before? When an external display is connected, and set to be above the screen with the menubar, a white dot will appear above and slightly to the left of the left corner of the menubar. The issue appears to be independent of the user's background, and when the position is changed in the displays settings page, the position of the pseudo-dead pixel will stay in the same position relative to the menu bar. Also, the mouse appears to move over it (including the spinner, so it's not color related). I tried killing all the menu bar items, it doesn't appear to be related to that. MacBook is linked to external display using 3rd party HDMI adapter, but it happens with VGA cable too. Anyone got any ideas?