In Windows I can enter a custom crop either by entering a ratio (1.5) or by entering the size or a representation of the size (1920x1080 or 16x9). This seems to be missing in the mac version. When I click the crop icon at the top, PL6 goes into crop mode but the drop-down (at the bottom) does not contain custom. It contains original, unconstrained, a load of presets and at the bottom, the option to clear custom - but no custom. The crop numbers just along the bottom are greyed out and I cannot click to enter different numbers. What am I doing wrong please?