Select, deselect, and reselect pixels

If a tool is not working as expected, you may have a hidden selection. Use the Deselect command and try the tool again.
Select all pixels on a layer within the canvas boundaries

    Select the layer in the Layers panel.
    Choose Select > All.

Deselect selections

    Do one of the following:
        Choose Select > Deselect.
        If you are using the Rectangle Marquee tool, the Elliptical Marquee tool, or the Lasso tool, click anywhere in the image outside the selected area.

Reselect the most recent selection

    Choose Select > Reselect.