startResize method
Starts a resize operation for any resizable node.
Works for any node with isResizable = true, including GroupNode
and CommentNode. The node must have Node.isResizable set to true.
Implementation
void startResize(String nodeId, ResizeHandle handle) {
final node = _nodes[nodeId];
if (node != null && node.isResizable) {
interaction.startResize(nodeId, handle);
}
}