Grouping needs to be more intuitive

**Is your feature request related to a problem? Please describe.**
Yes. Manual Grouping is not very intuitive right now. Currently, if I have created a group of multiple regions, if I cut (Ctrl + X) a parent region by mistake, the entire group is broken (thankfully, I can undo this with Ctrl + Z). I am not able to form groups very easily, if I have a long list of regions, I have to drag some element all the way from bottom to my group.

**Describe the solution you'd like**
I feel that we should be able to cut (Ctrl + X) a rectangle/polygon region and paste it inside another region (by selecting it) to start/continue grouping. Also, when we cut an element which has some children, then it should be cut and pasted with all its children intact instead of breaking up the grouping, this would help in case I am creating a hierarchy where I want a whole group to go and sit inside another group (right now I have to drag the first group to place it inside another).

**Describe alternatives you've considered**
I have considered tagging relations in multi-page documents, however, the arrows do not render when doing this. I have noticed on some other tools such as labelbox, they still render the arrow for multi-page relations by making an arrow from the starting node to page boundary (containing reference to the ending node) and then on the ending node's page, there is a continued arrow from page boundary (containing reference to the starting node) to ending node.
Therefore, to bypass the multi-page relations not working. I tried grouping the inter-page elements with relations and started running into above issues.