Cartographica has a feature that is intended to make it easier to distinguish between the feature being edited and the data on other layers that causes all features to be obscured using a semi-tranparent tint during editing. However, there are times when this can obscure data too much to be useful. Fortunately, this tint is user controlled and can be any color and any opacity, to suit your specific needs and applications.
To change the edit backdrop color, go to Preferences and click on the Edit Backdrop Color. A standard Apple color picker window will come up, along with a slider on the bottom to adjust the opacity. If you want no backdrop, just change the opacity to 0%.
By default, most polygonal features have an opaque, white background when you add them to a layer. At times, this may be distracting, especially when creating complex shapes. Since Cartographica edits features in the colors that they will eventually appear on the map, you can resolve this issue by changing the fill color in the Styles for the layer that you are editing. Double-click on the layer in the layer stack, or click on the Styles... button at the bottom of the layer stack and then change the fill color for "non-matching" features (assuming you are creating new features, otherwise, choose the sub-style that will be displayed).