Painter 6 glitch with Grid Options

Robin Harris describes a problem with Painter 6 that he says was confirmed by Corel Support: "Setting your units in Grid Options to any other option but pixels and then changing Horizontal and Vertical Grid Values causes the line thickness to multiply exponentially, leading to line thickness values of 0.945 or 4.016. This covers the page in a field of blue. The only way around this is to re-enter the Grid Options and change the units for line thickness to Pixels and set that to your preference without altering the Horizontal or Vertical fields (if you touch horizontal or Vertical field numbers you will be back to square one)."