You can edit more elements of the same article in the source pane at once as explained in Edit more elements at once in the source pane (Articles main tab).

To switch to any of open elements, just click any of its words in the window.

Bug fixing

Since the build 2231 (1.6, 2.0 and newer), the undesired movement of the insertion point in the open article elements is fixed. Now, the insertion point position is maintained in existing article elements when you add a new article element or switch to the elements of another article.