Base node for containers. Base node for containers. A [Container] contains other controls and automatically arranges them in a certain way. A Control can inherit this to create custom container classes. Fit a child control in a given rect. This is mainly a helper for creating custom container classes. Queue resort of the contained children. This is called automatically anyway, but can be called upon request. Emitted when children are going to be sorted. Emitted when sorting the children is needed. Notification just before children are going to be sorted, in case there's something to process beforehand. Notification for when sorting the children, it must be obeyed immediately.