Zooming via the mouse wheel has always worked by clicking, not wheeling. I plan to make wheeling work right, for zooming both in and out, but I have to figure out how to get those events into VB. VB6 predates mice with wheels, so it was tons easier just to handle the mouse wheel as a button.
The perf difference w.r.t. mouse wheel zoom-in speed in 2.43m will only be noticable on large, slow running sims. Small, fast running sims should zoom-in fast in any version.
To be clear, the perf improvement w.r.t. sim execution speed when zoomed in was implemented in version 2.43m. You should not expereicne any perf difference in sim execution speed in prior versions but you should see it in 2.43m.
Were you running the new graphics (the plant button) when the crash overflow occurred? If you can reproduce the crash or describe a set of reproduction steps, I would be quite happy to fix it...