Fairly newbie question here! I always use a small number of layers when painting, never more than 3 or 4.
However I'm wondering how to select something across all of these at once, so that I am able to resize selections on the whole image.
You are able to resize selections by using the "Selection Adjuster" tool (the shortcut key is "S" by default, I believe); however this will only change the selection size and shape, not the content within.
Unfortunately, to my knowledge you are not able to transform more than one layer at a time in Painter 12...this is only possible in Painter X3 or newer.
Darn, I wrote a sizable reply and the page crashed as I clicked post!
I'll get back to you later when my enthusiasm tank tops up again.
Note to self for when I re- reply: "how I do it; suggestion box and why it might be difficult to fix; floating layers and auto merge."
Righto, time to have another go at replying!
Now, this is a bit fiddly unfortunately, but it's how I do the job.
Firstly select the area you need to move, cut and paste it onto a new layer. (Ctrl+X, then Ctrl+V)
Painter always pastes into the exact same spot you cut it from, quite differently from Photoshop which pastes in the centre of the screen. (at least the aged CS3 version, the last version of PS I bought). Or else float the selected area and drag it up or down the layer pile and it'll become a new actual layer.
Reselect (Shift/Ctrl+D) and cut and paste from the next layer... and so on.
Make sure the new layers are adjacent to each other, or even better, grouped, select 'em and move them.
If you need you can then merge them back with the original layer (Ctrl+E) but it can be handy still having them repositionable.
Reword your question as a request for possible changes in future versions and post it in the suggestion box: (https://painterfactory.com/painter_product_discussion/f/suggestion-box)
While I'm well used to working around it now it's still a few too many steps, so I'd definitely +1 your request, it's a good 'un.
There are reasons it might not be possible:
Painter floats a selected area as a sub-layer, it's quite a cool method, (and it charms my socks off) but when you select another layer that floated layer is automatically merged with its parent layer. Enabling multiple layer floats might mean disabling the automatic merge function... resulting in a mess of floating layers, larger file size etc. Also, in order to move several layers simultaneously they have to be adjacent to each other, which floated sub-layers AREN'T- by definition their parent layer is always between them and the next layer above.
Best of luck, I hope the software works out for you!