A diagram element could only be drawn fully solid. Anything that should let the picture underneath show through - a container or a grouping drawn over the shapes it holds, an element you want to push into the background - had to be faked by mixing its colour with the background, which stops working as soon as the background is not a flat colour.

Every diagram element now carries its own opacity: a slider from transparent to opaque, next to where you pick its colours.

• For shapes, groupings and text blocks: in the shape properties dialog.
• For object types, fact types, concepts and containers: in the element properties dialog. With several elements selected, the opacity applies to all of them.

Only the solid fill fades. Borders, text and images stay fully readable, so a faded element remains legible.

The opacity belongs to the element, not to the colour, so a colour used in several places can be solid in one element and translucent in another. It is stored with the diagram and is included when the diagram is exported to SVG.

Existing diagrams are unaffected: everything without an explicit opacity stays fully opaque.