Hi Juan,
You should hold the SHIFT key while rescaling the element with your mouse.
It resizes the element pixel size such as Piano keys or Grid pixel size.
You can find attached an example layout as requested.
Lower Keyboard default starts on Octave 4
Upper Keyboard default starts on Octave 5
Juan Fdz.
How can I make a keyboard template having 2 octaves or 24 keys, to have 2 octaves at the top and 2 at the bottom, I'm trying to do it in EraeLab but it won't let me reduce the size of the keys, I think In the previous version it was possible. As it appears in the attached image