In Adobe Photoshop CS5, I can add, delete and rename swatches. However, I don't see an option to edit them. Is it possible to edit the color of an existing swatch?
To put it in simplest of words:
It's probably because it's a lot easier to just create a new colour than to create an option to edit colour values.
You can rearrange the order by going to Edit -> Preset Manager... -> Set Preset Type to "Swatches" -> Drag and drop the swatch to where you want it.