Zoom slider for LeiaPix Converter

Hello, I like to use LeiaPix Converter, but I find too difficult to retouch some details, especially small ones.
I know there’s a zoom button at bottom-left, but it is not enough, there should be a zoom slider to easily correct a part of the image.

In addition, a related problem is the great difficulty in adjusting the pen size at smaller sizes::
Adjusting with the mouse this bar is too imprecise at small sizes, which is the most needed (personally, I never need to use above the medium size, is too big), the size adjustment is so sensitive at small sizes that most times I end looking very carefully at the screen to slowly try to move the mouse 1 single pixel, and the hand mouse icon blocking the bar itself doesn’t help.

Join this difficulty of selecting small sizes, with the inability to zoom a part of the image that would allow to work faster and in a more precise way, and it results in more editing mistakes, and slower imprecise editing.