Eraser tool changes

When I choose the block eraser my cursor turns into a block and that's great. When I begin to try and erase something the cursor changes back to an arrow. This just started. Did I inadvertantly change something? How can I get this to stop and have it remain the square block when I am erasing within a file?

Thanks,
Andrew

This just started.

Trash your preferences. That's always the first thing to do when something begins acting up suddenly.

I did that and it still was messed up. However I rebooted and it seems fine now.

Thanks,
Andrew