Thanks for writing! Sorry for the delay in my response, it's been a busy week!
Vertical zooming is currently supported through the xmega's programmable gain amplifier - a 1x to 64x hardware gain that happens before the analog to digital conversion takes place. This feature is exposed in a dropdown box in the pane on the right side of Pixelpulse for both voltage channels. Note that each increase in gain results in a corresponding decrease in range. Additionally, use of this hardware gain will zoom the x-y plot.
Kevin, the better looking half of Nonolith, is hard at work on a nontrivial overhaul of Pixelpulse which will bring data export, advanced waveform setting functionality, and more to a Chrome tab near you, within the next week or two.
As for setting current - the exact settling time of our current control loop depends upon the impedance of the attached load and as such gives an effective maximum frequency of anywhere from 100Hz to 10KHz. What's your expected use case?