Zoom in the molecule

Zoom is currently not very easy I find.

One way to make it more intuitive would be that when you have the zoom tool selected the scrolling wheel acts as a zoom.

No idea how easy it would be to implement @rufenerc

Start by locating the zoom tool and its existing interaction handling, then trace how scrolling-wheel events are processed when that tool is selected. Done means the wheel provides intuitive molecule zooming in that mode without changing behavior elsewhere; add or update the relevant interaction test if the project has one.

Written by the indexing model from the issue text.