Drag color around like tracing layer

I’m kind of new with Rebelle and i love playing with the watercolor simulation especially. I found the tracing layer feature lately and it reminds me of a feature i like to use in other paint program which is about dragging paint from current layer or from underlying one. I found that the tracing layer was doing the same thing but you get limited to dragging color from the tracing layer only. Would be really interesting to be able to drag color from current layer also or all underlying layer. 

Here are some examples of what i did with in procreate using that feature. I’d be really curious to see what could be done  with watercolor in the same fashion.

https://imgur.com/a/gzEwrw8

Thank you for the idea!