The Clear command deletes everything in the current selection. If there is no current selection, the contents of the active layer are removed. If the active layer has an alpha channel, the deleted selection is made transparent. You can restore the original colour to the transparent area using the Eraser tool, by setting it to Anti-Erase. If the layer does not have an alpha channel, the deleted area is filled using the current background colour.

Clearing a selection does not delete the selection itself. Unlike “Cut”, “Clear” does not place the deleted contents in the Clipboard and the contents of the clipboard are unaffected.