... Wynne Paul Boyd wrote: I'm not sure if what I've just discovered is a bug or a feature Hi Paul, It's probably both. When you set any grid spacings... you are in fact making two entirely separate settings: 1. the units to be used for the grid labels, and 2. the distance between the grid lines. There may be a case for putting them on two separate menu items. To cancel the change from feet to mm, you needed to click cancel on this first dialog: 2_181220_080000000.png Once you have gone beyond that and not clicked the yellow cancel bar, the change of units has been accepted. In the next dialog you can change only the spacings, or cancel and leave the spacings unchanged but now shown in the new units (0.5ft= 6 inches= 152.4mm). If that's not what you wanted, you must start again at pad> pad grid options>. If you want to change the spacings but not the current units, you must click the relevant units bar each time. regards ...