page placement mechanism for avoiding overlapping problem

After expanding page, there is a need to adjust the spacing between page and other components to avoid overlapping problem. Here is a simple solution (needs to be discussed).

Each collapsed page is assigned to a placement state.When the page is expanded and has an overlap problem, its collapsed placement state would be remembered. Then the page will automatically move to a new location to avoid overlapping,for example,the rightmost side of the model. There is no movement for any other component, since we don't expect to change the layout for whole model. The page will be back to its initial location when collapsing it.