/** Returns one of this node's siblings in its parent's child list.
The delta specifies how far to move through the list, so a value of 1 would return the node
that follows this one, -1 would return the node before it, 0 will return this node itself, etc.
If the requested position is beyond the range of available nodes, this will return ValueTree::invalid.
*/
ValueTree getSibling (int delta) const noexcept;
should probably be:
/** Returns one of this node's siblings in its parent's child list.
The delta specifies how far to move through the list, so a value of 1 would return the node
that follows this one, -1 would return the node before it, 0 will return this node itself, etc.
If the requested position is beyond the range of available nodes, this will return an invalid
ValueTree().
*/
ValueTree getSibling (int delta) const noexcept;
since ValueTree::invalid is only valid if the flag JUCE_ALLOW_STATIC_NULL_VARIABLES is set
Rail