> It can be sized to fit the small window though this doesn't do you
> much good in File view.

Depends on your resolution and size screen.

Surface Pro 3 is 12" diagonal with 2160 x 1440. Therefore, there are still plenty of space with both ZTree and OSK displayed simultaneously.

The possible challenge for enthusiast ZTree users with upcoming full integration of Windows ecosystem on different devices (from phone to computer) is that more smaller and touch-based devices will be technically able to support ZTree, while at same time not benefiting fully, or even being handicapped, from its keyboard-based paradigm.

My personal point of view on this is rather conservative. ZTree is designed with computer in mind, not phone or tablet. For the later ones, touch-based file managers seem more logical to me.

On my Surface, I use a mix of Win8 file managers, Windows Explorer and ZTree, depending on the context and usage. For instance, I would definitively not try to use ZTree when browsing my tablet only with fingers.

Note that in this context, I find John Gruener's ZTREE.INF suddenly highly productive. (change last lines to reflect your preferences). It allows me to switch easily from Window Explorer to ZTree. For the opposite, ZTree to Explorer, Shift-F10/right-click|Open is perfect.