# Viewing and Editing Packets

Each time you open a packet, you will see three buttons at the bottom of the window: Commit, Refresh and Close (all illustrated below). Pressing Close will simply close the packet again. Pressing Refresh will reload the contents of the packet from Regina's mathematical engine (this should rarely be necessary, but the button is provided just in case). Commit should be disabled until you start making changes.

Once you begin to edit the packet, the buttons will change to Commit, Discard and Close (again illustrated below). Your changes will not not take effect until you press Commit (after which you will not be able to undo them). Alternatively, you can undo your changes and revert to the original state of the packet by pressing Discard.

### Uneditable Packets

Sometimes you will find that you cannot make changes to a packet at all. This often happens when a packet is constrained by its children. For instance, if a triangulation is parent to a normal surface list or an angle structure list then Regina will insist that the triangulation does not change (so that normal coordinates and angle structure coordinates cannot be invalidated). Uneditable packets like this will be marked with a small padlock in the tree: see the Figure 8 Knot Complement in the illustration below.

If you find yourself in such a situation, you can always clone the packet. This will create a new copy of the packet without any children, and you will be able to edit your clone instead.