Right-clicking an object in the list opens the context menu:
Copy to - copies the selected object (or several objects) to the current menu or to another one (more details...).
Copy state to - copies the properties of the selected state to another state (more details...).
Copy name(s) - copies the name(s) of the item(s) to the clipboard. Simple - just the name. For Java - converted to the internal representation.
Copy navigation to this button - copies the link to this button so you can paste it into any action where you want to navigate to this button.
Copy positions to popup / main menu - moves the objects with the same names in the popup with the same name as the current main menu (or in the main menu with the same name as the current popup) to the positions of the selected objects. Only the selected button states are copied; with "Move entire button" on, all states of a selected button are copied.
Delete - deletes the object.
Change object state - opens a window where you can change the properties of the object.
Change effects - opens a window where you can change the object effects.
Copy properties to clipboard, Paste properties from clipboard - described here.
Animation groups - adds the object to, or removes it from, the selected animation group. You can use hotkeys for this.
Align objects - aligns the selected objects. Please note that the alignment uses the order of the object list. If you have selected a background grid of 1280x720 or 1440x1080, the screen size used in the calculation is 1280x720 or 1440x1080 respectively. Otherwise 1920x1080 is used.
Link objects - lets you link static objects to a button state. This way you can use more than one image (text, rectangle) for a state. When the parent object is animated or moved, the child objects are animated/moved as well.
Link to - opens a dialog where you can specify a parent state for the selected static object.
Unlink - unlinks the objects.
Linked objects - lets you specify the child objects of the selected object state.
Left/Right/Up/Down/OK (enter)/On select actions - show the actions assigned to the selected button. You can change an action by clicking it.