In several threads here, there is a work-around posted for selenium drag and drop with pages that use HTML5 for drag and drop. This work-around involves using javascript to simulate the drag and drop, for example Unable to perform HTML5 drag and drop using javascript for Selenium WebDriver test, and https://gist.github.com/rcorreia/2362544. This solution works well on this page, http://the-internet.herokuapp.com/drag_and_drop.
The general approach is to read the javascript file here (https://gist.github.com/rcorreia/2362544#file-drag_and_drop_helper-js) into a string, referred to as 'jsfile' below.
then in selenium (with java), pass in the css selectors for the source and the destination, where #column-a is the id of the source and #column-b is the target.
((JavascriptExecutor) driver).executeScript(jsfile +"$('#column-a').simulateDragDrop({ dropTarget: '#column-b'});");
It works like a champ on that page.
However, a similar approach does not seem to work on this page, https://crossbrowsertesting.github.io/drag-and-drop.html. Nothing happens when I run
((JavascriptExecutor) driver).executeScript(jsfile +"$('#draggable').simulateDragDrop({ dropTarget: '#droppable'});");
I have pages that seem to behave like this second page (eg no drag and drop). As a first step in understanding this, I'd like to get an idea why this approach does not seem to work in the latter case here.