Multi-layer selection

[Jehan <jehan girinstud io>]

Hello all,

Let's kickstart this mailing list with a discussion about an absence of 
feature that has annoyed Aryeom for very long. So I know she will enjoy 
participate to this one. :-)

Right now, you cannot multi-select layers.
The feature request: https://bugzilla.gnome.org/show_bug.cgi?id=730216

Multi layer selection's main advantage would be to move several layers 
at once, which happens when you work with dozens of layers, then 
suddenly realize you need to organize your layers under layer groups. 
Right now you can only move them one at a times, which is tedious. You'd 
expect to be able to shift and ctrl-click layers (in a similar fashion 
as in a file browser).

There has been a new feature request recently about having linked layers 
play such role, so that moving several link layers move them all 
together: https://bugzilla.gnome.org/show_bug.cgi?id=755972

This makes sense too. I am not sure if this is as discoverable as the 
concept of "selection", which most users know from using it in every 
software (and advanced users would expect a few behavior patterns, like 
shift-click = select all items between current selection and click; or 
ctrl-click = on/of selection on clicked item while keeping existing 
selection, etc.). Hence many people would try to multi-select 
intuitively and discover it does not work.

So should we have these 2 concepts?
If we have multi-selection, do you have a concept of "main selected 
layer", which is the one where drawing occurs? Is it then the first of 
the last selected layer?
And so on, many questions to be answered which could end up in a 
specification to allow new behaviors. :-)

Thanks!

Jehan