debugPaintFocusBoxes top-level property

Causes each Focus widget to paint a box around its bounds.

Different colors indicate different focus states:

• Green: the node has primary focus.
• Blue: the node is in the focus chain but does not have primary focus (i.e., it is an ancestor of the primary focus).
• Cyan: the node is focusable and participates in focus traversal.
• Yellow: the node skips focus traversal (FocusNode.skipTraversal is true) but can still receive focus directly.
• Red: the node cannot receive focus (FocusNode.canRequestFocus is false).

Enabling this causes each Focus widget to wrap its child with a widget, which can cause state loss if the child is a stateful widget that isn't keyed.

This has no effect in release builds.

See also:

• FocusNode, which manages focus for a widget subtree.
• debugFocusChanges, which logs to the console when focus changes occur.