Every item has its context menu. It can be opened by clicking the right mouse button (lefthander mouse - by left mouse button) while the cursor is over an item on the scene, or over a selected group.
By a context menu, you can change some of the basic settings of one item or of all selected items. You can change the layer of the current item(s). Also, you will find the ability for the quick creation of a new layer for a selected group of item(s). Context menu of warp points allows you to quickly jump to the opposite side of a warp entry.