Use the Edit > Delete command when you want to delete a segment out of an image, or other objects, e.g., drawing objects. Anything that has been deleted will not be copied into the clipboard.
Deleting an image segment
1.Activate the image out of which you want to remove the segment.
2.Activate the Toolbox toolbar. To do this, use, e.g., the View > Toolbars > Toolbox command.
3.Click the Rectangular Marquee 
button on the Toolbox toolbar.
4.With the left mouse button depressed, outline the image segment that you want to delete.
5.The selected image segment will be outlined with a broken line.
5.Use the Edit > Delete command, or the [Del] key.
6.The image segment you selected will be deleted from the image.
Please note ...
Note: When you delete image segments, please pay attention to the points listed below:
Specifics for various image types
With time stacks, the image segment will only be deleted out of the frame that is currently on display. In the other frames, the image segment will remain unchanged.
With multi-layer images, the image segment will only be deleted from the active image layer. In the other image layers, the image segment will remain unchanged. In the Layers tool window, the active image layer is indicated by a check 
. You can also use this tool window to change the active image layer.
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