Can you be more specific of what "properly manage a palette" means?
Thank you for your info, that was very useful!
I was able to activate my steam key. I don't like starting software through steam, but I guess it will just be a matter of time before I can access the new version somewhere else

. The
frame previewing function is super useful! I do have a couple of comments on it:
Could it work that you have a complete frame overview somewhere? Like if I have 7 layers, I migth not want to view them separately but still want a quick frame overview from all layers together.
Could I set myself what kind of bg I want for transparant? Small objects are hard to read on the checkerboard background, I would set this to white myself.
Why is the checkerboard surface larger than the actual image? If I set the zoom even higher the checkerboard space grows yet the image doesn't!
Now onwards to palette control:
I had never realized I could drag and drop colors. Dragging and dropping from the edges is not very intuitive to me, it took me a while to figure how to copy colors even after watching your demonstration! I would have found it sooner if I could move holding shift and copy holding control, but could just select in the middle of any selected color. I have this same issue with moving frames/layers.
My ideal palette functions would look a bit like Grafx2's. I am missing (or havn't found yet):
Move indexes around. If I want to reorganize my palette, I would need to move the position of the indexes in the palette. This would be useful for creating new ramps with the gradient function too.
Merge colors, I actually meant merge indexes. For example I might have 2 sprites from different sources in my canvas and I want them both to use the same palette. I'd like to drag the new colors onto the old colors (which is already possible with the copy function) and then remove the old ones, which is essentially merging indexes. Of course I can remove all duplicate colors at once through "create palette from current sprite", which is a good start.
Removing indexes... the only way to remove colors now is to first move them to move them to the end and then slide them away? But again, this doesn't work with indexes. if your drawing is already finished, its wonky.
As for color picking, I'd love to have the "palette editor" on screen all the time. It could replace the color picker at the left bottom, which confuses me anyway. The palette editor remains nice for adjusting relative color on multiple colors at once.
Really nifty in GraphicsGale is its load palette function. In their interface you can manually remap your sprite, or copy only specific colors, or leave specific old colors intact, when you import another color.

In grafx2 I use some tricks to get a similar effect, mostly moving the palette to a different spot in the image and then copying a selection of colors, or making a custom brush and then importing the brush colors. The easiest way in asesprite to do this is to switch to full color mode, then paste an external image in the canvas you're working on, and then switch back to index mode. I guess that works, but doesn't give you full control.
Lastly, not mentioned earlier yet: Hold shift in draw mode to create a straight line would make my life easier.
Thanks so much for developing this tool, now that I know of frame preview, I'll give it another shot. It does have a lot of fancy features indeed..
EDIT:
Another thing that has bothered me a lot in Aseprite when editing tilesets, is that I can't snap selections to a grid! I can make perfect 32x32 selections, but then moving my tile over the canvas I have to place it perfectly manually.. :/