Example: I have 3 squares. 2 large ones and one small one overlapping the two. (see picture)
The task is to set the small red square to exactly 140 x 140 mm without losing the proportions in size or position to the blue or green box.

I want an exact scale up where the end result is that the red square is 140 mm x 140 mm.
I can use rulers, but the small square doesn't snap since it isn't touching the bounding box. Using this I can eyeball it and get a result like 140.062 x 140.062 mm. I need it to be 140 x 140 mm flat. And this method takes time, dragging the size back and forth since the middle square isn’t centered.
Same issue if I were to draw a 140 x 140 mm square and try to match the red one to it. It will snap in one corner of the drawn 140 x 140 mm square guide, but move away from that corner when scaled.
In this example I can of course calculate the increase to 140% and scale accordingly. Works great for this simple example, but it is much more tedious when I want to scale a text for instance or objects with uneven numbers, where I need a stack height to be e.g. 100 mm tall. Here the text often is something like 14.532 mm to start and I have to calculate 100/14.532 = scale up of 688,1365%. Just takes a lot of time.
And for items that needs scaling in two directions I need to make two separate calculations (if I wanted the new dimensions of the square to be e.g 140 x 190 mm)
What I propose is a tool/possibility to use the same technique as when aligning object, combined with the properties tab.
1. I select all 3 objects using shift or simply dragging the selection box over
them.
2. I then click the red box again without holding shift, making it an indicated selection (like when aligning objects)
3. I open up the properties tab. Either the W x H is then changed to show the dimensions of the red box, or a new input area opens up so both the entire groups outer dimensions is shown as well as the dimensions of the red square.
4. I proceed to enter my desired values in the input boxes, setting the new dimensions for the red square
5. The program scales the entire group according to the new set dimensions of the red square.