The command raises the active
layer to the top of the layer stack. If the active layer is already at
the top or if there is only one layer, this menu entry is insensitive
and grayed out. If the active layer is at the bottom of the stack and it
does not have an alpha channel, you cannot raise it until you add an
alpha channel to it.
7.17.1. Activating the Command
You can access this command from the image menubar through
→ → ,
or by pressing the Shift key and clicking on the
up-arrow icon at the bottom of the Layers dialog.