Affinity Photo Refine Selection on Mask question

[AlexVith]

Hi!

I keep stumbling upon a recurrent issue when trying to work with masks in Affinity Photo. The issue is as follows: I create a mask from a selection, I then right click on the mask and select "Refine Selection". In the Refine Selection dialog box the Matte Edges is on by default. Most times, then switching the preview to Transparent I get the exact mask adjustment I want, i.e the mask looks just right. Naturally, I click Apply, but the actual resulting mask is nowhere as I previewed it. Do you know what is this issue about? What am i doing wrong? 

In the example below you can see, in the first picture, how the borders of the wipe look clean. As soon as I apply the mask, I get those darker outlines (which are part of the background I am trying to get rid of).

Edited May 16, 2024 by AlexVith

[lepr]

The preview ignores the actual output choice and always shows the result you'll get if the output is set to 'New Layer with Mask', which involves edge decontamination.

In other words, if you are happy with the preview, ensure output is set to 'New layer with Mask' to get what you see.