Excellent! Puntuado con 5 de 5 estrellas

I used the add-on Barlesque earlier, but since the development of Barlesque has stopped I switched on to The Puzzle Piece and believe me, this one is far better than any other similar add-on! Thanks to the developer for such a great add-on!

Can you please provide the colourful toolbar button icon set present in your add-on OmniSidebar for this one too :)

Esta valoración es de una versión anterior del complemento (1.0.2). 

I'm glad you like the add-on!

If you mean an option to change the native firefox icons to their colorful versions when they're in the add-on bar, yeah I may do that, seems like a good idea.

Of course, I'll only provide the option to change the native black- and blue-based icons to colorful ones. Changing colorful buttons to the default firefox button style (like the equivalent option in OmniSidebar) I probably won't do. This is because, unlike the sidebar buttons in OmniSidebar, which there aren't that many of, pretty much every button out there from add-ons can also be placed in the add-on bar as well. Making black- and blue- based icons for all of these existing possible buttons would be too much work. (If someone decides to create some kind of button or icon pack like this that could be used for a similar icon replacement, I'd be happy to include it in the add-on if they so wish it, but that probably belongs more in the context of a theme rather than this add-on).