What is a Yellow Selection and How to Deselect It?

[TechnicGeek]

I have often yellow selection appearing that I want to get rid of because I can't seem to work outside of that selection. So far it appeared when I pasted new later and had to anchor it. The selection still stayed there after anchoring. Another time it appeared was when I resized canvas. New canvas was alpha color and I could not paint it white because I could not work outside of that selection. This is a selection that I am talking about:

   

Why do I need this selection and how to deselect it?

Thanks.

[rich2005]

That is the layer boundary marker. Only exists in Gimp, is not part of the image.

It is useful to know, therefore the default setting.

If you need to turn it off, go to the View menu and untick Show Layer Boundary

Looks like you want to increase the layer size to that of the canvas. Use Layer -> Layer to image size

[Espermaschine]

Its the layer boundary.

Either 'Layer to Imagesize'

or turn it off under (can be useful for positioning text): View -> Show Layer Boundary

Edit: rich, super-ninja