can't figure out how to use marquee tool to delete part of a layer

[newwebdesigner]

Hello all,

All I am trying to do is figure out how to use the marquee tool to delete the bottom 2/3rds of a rounded rectangle.

Here's what I am doing:

Clicking on the rounded rectangle and drawing it to the size I want

selecting the marquee tool and selecting the area of the rounded rectangle I want to delete.

After I selected the area with the marquee tool, I press delete and instead of the area I selected being deleted, the whole layer is deleted instead. Does anybody have any idea what I am talking about, and can anybody help me?

Thanks

 

[Nomission]

The delete button on erases selections on raster layers.
On shape layers it will delete the shape.
(To learn the differences visit this website)
To delete part of a shape, edit it with direct selection or pen tools or use this method:
instead of the marquee tool select the rectangle tool.
Make sure the shape is selected (click on it's thumbnail in the layers panel)
press Alt (and keep it pressed) and start drawing your area, release the Alt button soon after the starting click and that's it.