expand(nodes, option) does not respect the passed options

[OskarHowe]

Hi,
I have observed, that the expand(nodes, options) function does not apply correctly the passed options, when called.

Reproduce the issue:

1. Display the graph with a layout and specify this layout in the options object layoutBy : {name: dagre} field
2. Collapse all nodes and edges with
   2.1. collapseAll(options)
   2.2. collapseAllEdges()
3. Change the layoutBy field in the options object, layoutBy : {name: breadthfirst}
4. Expand any collapsed nodeA using
   4.1. expandEdgesBetweenNodes([nodeA, ...neighbors]))
   4.2. expand(nodeA, options)
5. Notice that the graph you see is still in the dagre layout.

When you use instead:

3. ...
4. Expand all collapsed nodes using
   4.1. expandAllEdges()
   4.2. expandAll(options)
5. Notice that the new layout has been applied.

Possible reason
By having a quick look into your source code, I assume the problem results from these lines in the file: expandCollapseUtilities.js, function: expandNodeBaseFunction, lines 46 – 48:

if (single) { this.endOperation(layoutBy, node); }

In any other expand function, see expandAll(options), the nodes will always be rearranged by the endOperation after expanding. Here, the rearrangement is conditional, which may cause this bug.