[Animations] Introduce merge down to multiple layers facility
Operating System: Ubuntu 20.04.01
Description of the feature
Sample: I have a GIF sticker and i want to add some texts to it Once wrote text using "text tool" then it create a new layer and we can right click on that layer then select 'merge down' but it apply to one layer bottom to it.
(the GIF has 20 layers as frames including background image)
Basically selected layer necessary to merge to all layers without affect or copy other layers contents each other. Currently if has 20 layers then i have to create 19 duplicates of required layer and merge down one by one
For animations (create or edit gifs)