Eraser tool not erasing

I am having problems with the Eraser tool not erasing
After erasing, once I moved the Eraser tool away from the erased area, the lines comes back. Ive been drawing in the line art layer only, I did the same testing on the other layers, and the same result. It seems to be more of a bug than anything else.

sample:
http://screencast.com/t/ywA0zAy2X

I just found what it was, which I didn’t find in the documentation.
In the Eraser’s Tool properties, there was an option title: Keep Vectors that was checked by default. Once unchecked, I had no problem erasing.

I find this very annoying because the Eraser should at least erase the lines drawn by the brush tool while maybe leaving he lines drawn by the pencil tool.

I guess they have this option because of the new feature to have vector drawing layers and raster layers.