Why can't I place a block inside of another container?

In Hopscotch Web, there is a project hierarchy. Only certain blocks can be placed inside other ones.

Blocks

Blocks make things happen when the project is played. For example, "Set Size percent 200" will make an object grow to twice its size.

Rules

Rules are pink containers starting with "When" – for example, "When game starts". Code inside the rules gets activated when the event happens.

Rules can contain blocks.

Objects

Objects can be characters, shapes or text objects.

Objects can contain rules.

Scenes

Scenes are like stages or levels in your game or project. Scenes can contain objects.