Is it currently possible to drag a portlet from another part of the page and drop it onto another view already containing portlets, and have the existing portlets behave as if moving/reordering whilst introducing the new one?
For example, having a palette of portlets in a left-hand panel and dragging one onto a container of pre-defined portlets, and having those portlets move about to make space for the new one? Ideally, the dragged portlet would be duplicated for the drag (rather than removed from the palette).
Yes, it possible to move portlet from one part of the app to another.
the dragged portlet would be duplicated
Currently you can only move portlet, there is no way to copy its content ( content of portlet can contain any set of Webix component, with different settings, event handlers, callbacks, etc., so there is no simple way to clone such kind of portlet.
When you drop portlet to the new location, it will fire onBeforePortletMove event. You can attach a custom code to the event, block portlet moving and instead of it call .addView on the target view, to add a new view in the necessary location.
Any chance you could provide an example of a portlet in one section of a layout and the ability to drag it to another? All the portlet examples I reviewed demo portlets within one section of a layout. (Your complex example appears to be not so complex).