Now, since the red area indicates the area that is masked out, Image > Adjustements > Invert (ctrl-I or Cmd-I) will make this a proper selection:
Click image for larger version. 

Name:	19 Mask inverted..png 
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Exiting the layer mask and filling the selection with white produces:
Click image for larger version. 

Name:	20 Selection fill.png 
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Size:	652.7 KB 
ID:	22546