The Edit Operations allow for easy manipulation of the image history, the selected region of the image, the selection itself, and the clipboard.
An important thing to note about selected regions is that all drawing operations are clipped to remain within them. For example, if you use the Ellipse Select tool to select a circular region in the middle of the image, you will be unable to draw anything outside of that circle while the selection is active. Effects and Adjustments will only affect the selected area as well.
This undoes the most recent action that you've taken that affects the image, if any. This functionality is also available from the History Window.
This redoes the most recent action that you've undone, if any. This functionality is also available from the History Window.
You may use this to remove a selected portion of the active layer. You can select a portion of the layer by using the Rectangle Select, Lasso Select, Ellipse Select, or Magic Wand tools. Once you perform the cut operation, that area of the layer is moved to the clipboard and replaced with transparent pixels. The current selection outline is also removed.
This is similar to the Cut command, except that the selected region remains on the active layer and the selection outline is not removed.
If there is an image in the clipboard, this command will allow you to paste it on to the active layer. The pasted pixels will then be selected and the Move Selected Pixels tool will automatically be selected. This will allow you to move, scale, or rotate the pixels into the desired location and orientation.
If the image being pasted is too wide and/or too tall for the current canvas size, you will be asked if you want to resize the canvas. This is a quick shortcut to the Image → Canvas Size command so that you can make sure that what you are pasting will fit.
This is similar to Paste, except that it creates a new layer, makes it active, and then performs the Paste command.
This is similar to Paste, except that it first creates a new image, makes it active, and then pastes the contents of the clipboard in to it. The new image is exactly the same size as the image that is in the clipboard.
This command erases the currently selected region of the active layer. All pixels that lie within the selected region are replaced with transparency. This is similar to the Cut command, except that the selected pixels are not copied to the clipboard.
If there is a selected region, this will fill it with the current primary color.
If there is a selected region, this will cause all pixels that are selected to be unselected, and vice-versa.
This causes the entire canvas to be selected.
After you select this menu item, no pixels will be selected.