khs_

Hello VertigoBirdie,
Welcome to Affinity Forums.
To make the background transparent go to File -> Document Setup (or with the Move Tool selected click anywhere outside the document to deselect everything and then click the Document Setup button in the context toolbar) and in the color section check Transparent background checkbox.

Yes,
 
Also, when you have made the background transparent, if you switch to the Export Persona, you will see that one "slice" has been auto-created - it is a slice which covers the whole document. Select this slice, then at the top, choose "PNG" and choose a "Matte" colour - your file will then export with the colour as the background :)
 
Thanks,
 
AndyS

Hm from a usability stand point this is not good.
 
I should not have to set the document background to transparent for exporting a transparent PNG slice.
 
The exporter should be able to ignore the background of the artboard intead guys!

Hello MEB and Affinity Team,
 
About this feature, would it be possible to simply Alt-Drag the "fx" icon from a layer to another to duplicate the effect? Also, just moving the "fx" icon should just move the effect to another layer. Photoshop has this feature since a long while.
 
Thanks guys!