Heal and Clone effect not seen on low frequency layer

[Hwrocco]

Hi, I had just purchased the Affinity Photo from Apple Store and viewed the tutorial video about how to edit the photos by ways of frequency separation.  With reason unknown, whenever I attempted to do some healing or cloning actions on the low frequency layer, no effect could be seen after I click and drag on the selected area.  As well as the inpainting brush, the selected area would not turn red as it performed on the high frequency layer.    Grateful if any of you could give me some ideas about what had I done wrong, many thanks 

[barninga]

i cannot reproduce the behavior you described.

be sure you select the layer -click on it in the layer stack- where you want to use any tool before you begin.