Best practice for nested, modifyable 2d rectangles in an editor

Question

Overview

Summary

• User can resize, move and add boxes at will
• A box may have endless amount of sub-boxes
• Editing sub-boxes is currently done by opening another window
• Sub-boxes usually fill the entire "space" in the parent box

Questions

1. How to visualize sub-boxes without overwhelming the user with information?
2. How to allow the user to modify sub-boxes in the same window without getting ton of input errors?

Details

"Story"

I am currently creating a basic layout editor, that allows me to create an endless amount of boxes with endless amount of sub-boxes.

The user is supposed to manipulate (move & resize) all of these boxes at will. All of that works fairly well so far but to actually modify a "sub-box" I currently have to open another editor instance, that only caters for that specific box.

The Task

I want the user to be able to edit sub-boxes in the same window as the parent boxes, without overwhelming him with either information or hinder him with invalid input actions (e.g. modifying the size of a sub-box when actually the parent box was supposed to be moved). The actual problem gets more clear, when one looks at what those nested hierarchies actually could mean:

Answer 1

The one thing that jump's into my mind is the pattern of grouping. So if the user is on "toplevel" all actions are performed with the first level box. To manipulate sub boxes the user would have to "navigate" into the first level box. This could be achieved e.g. by a double click. To make clear, that the user is now inside the first level box, everything outside this first level box should be disabled. Now the user can perform actions with the sub boxes. To leave the box could be achieved by a double click somewhere outside the active first level box. To do so, a zoom functionality might be necessary.

If you think about group behaviour, you might come up with some tools that have grouping capabilities (like most of the prototyping tools around) and you might find different ways how to navigate in and out of groups.