Limited Customizability

The options for changing the color scheme are very limited. You can only choose colors for the display background, the display digits, and the basic function keys. For each of these, only nine very bright primary colors are available. It is impossible to make an elegant-looking calculator the fits in with the rest of the MacOS UI.

Edit: I just found a way to select the same themes that are available on the iOS version. They are on the View menu but are not available in the Preferences dialog.

Ultrakeet about PCalc