A small change in Layer dock code for proper functioning of delete button upto last layer

[Boudewijn Rempt]

On Saturday 19 March 2011 Mar, srikanth tiyyagura wrote:
> Hi to all,
> 
>           This is the code for solving the deletion issue upto the
> last layer in the layers dock.
> Please review this and if any correct me
> 
>   what I did is if the image layer reach the final Layer , then
> disabling the delete button

I think that's correct. I had a brief discussion about it on irc with Dmitry, but I do feel that it's bad usability to let the user create an entirely empty image file. There should be at least one layer. However, this patch isn't quite done yet: we need to make sure that the last layer staying up isn't a clone layer or a filter layer, I think.

-- 
Boudewijn Rempt | http://www.valdyas.org, http://www.krita.org