Size of dehaze box

This is an issue that drives me crazy: when I use the dehaze tool a small box with the image comes up in the middle of the screen.  The box is far too small and I can't understand for the life of me why there isn't an option to increase the image to full size while I work on the dehazing.  Or am I missing something and can the box be made to increase in size?  For people like me with less than perfect eyesight such a small box is useless.

If you say "a small box", I believe Anwesha is on the right track, your display is probably not optimal for your eyesight. For me, the dehaze Window is not small, it's more than a quarter of the screen area. That's good enough to judge both the detail level and the global effect on the full image. I don't need the 'trial and error' method to find the precise setting for the image.

Let's jump first to the technical (and artistic) explanation.

When you apply various enhancements or filters, like sharpening, levels, shake reduction, black and white conversion or many filters like noise reduction, the math calculations can be relatively simple or very complicated. Some are very quick, some may require ten seconds... On the other hand, the desired effect can be assessed when looking at a small area (sharpening or denoising) or at the whole image (that's the case for dehaze). To speed up the process, the dialogs can show the effect on a small part of the image; the moves of your sliders are nearly shown 'real time'. That's why you find different ways to show the effects depending on your tool or effect. The new 'dehaze' and 'shake reduction' processes are very low to process, but they require both a full image view and enough detail since they tend to produce unwanted artifacts if set too high.

Tip:

Apply the effect to a layer copy and use the opacity setting of the layer once the effect is applied. You can vary the intensity of the correction finely while zooming in as much as needed to control detail quality.

What is the resolution set on your machine?

Though the size of the dehaze dialog cannot be increased, you can change UI scale factor to 200% from Edit > Preferences > Display & Cursors

Now re-launch Editor.

Thanks,

Anwesha