Preserve diagram state

[kolovos]

Consider the following scenario where the user:

• Navigates to view A
• Zooms / scrolls within the view
• Navigates to view B
• Returns to view A

Currently, when returning to view A, the previous zoom/scroll state will be lost and the view will appear in its default zoom level and scroll position. This can be remedied by:

• Using a different
  to contain each view and showing/hiding divs as the user navigates through views
• Supporting multiple Golden Layout tabs

In both cases, it would be nice if the zoom/scroll state of views could be preserved when the content of the view is also updated (e.g. because of a change in its underlying model)