I have a simple shape (it is the surround for a rear projection screen). In front view, lines which should be hidden are shown as dark solid lines. I have tried toggling hidden line on and off and nothing helps. This is fundamentally my problem as it makes viewing and showing the model to others confusing. However, the plot thickens. I was putting together screen grabs to illustrate my problem and moved and rotated a copy of the surround. I was planning to cut a section to show what should and should not be hidden. In front view I drew a plane planning to move it to the center of the model, but as soon as I started drawing the plane the lines corrected themselves and all hidden lines were instantly hidden. I could toggle them on and off with a shortcut as one would expect. Even more odd is that this only works if the plane is behind the model.

I am guessing this could be a video card issue, but wanted to check here and see if there is a solution. I apologize if this has been discussed or is a known issue, and would appreciate being pointed to any prior posting regarding this issue on the forums.

I hope the attached images make the issue clear.
Image 1: Hidden lines off and solid lines which should display as hidden evident.
Image 2: Hidden lines on and solid lines which should display as hidden evident.
Image 3: Same as image 1 - only difference is I drew the plane on the right side of screen.
Image 4: Same as image 2 - only difference is I drew the plane on the right side of screen.

I am using the current V3 beta, but this also happens on V2.

Thanks in advance,
Mike W