Hi Justin,
Just tried this and the higher values have no effect. The Blur is applied up to 100 pixels only, even if I type higher values.
Here is what I did:
1. Loaded a ~20MP photo.
2. Created and selected a new pixel layer.
3. Used the Elliptical Marque tool to select a region in the centre of the image covering about 30%.
4. Pressed "Q" (Edit Selection As Layer)
5. Used the Gaussian Blur tool at 100 pixels
6. I then repeated the above typing in 1000 pixels in the Gaussian blur tool
The results are identical, i.e. Gaussian Blur is only applied in a 100 pixel area, even when higher values are entered.
Am I missing something?
Cheers, Thomas