Excellent question! There are a few limitations that we have to place on the ConPty to make it work quite right. Primarily, client apps running attached to the conpty will not be able to have separate viewport and buffer sizes. On *nix, the entire "console buffer" is just the size of the window, but on Windows, technically, the buffer is much larger than the window. (as an example, when you open up a command prompt, there's a giant empty space at the bottom if you scroll down). Fortunately, we haven't came across any apps that _need_ the buffer to be a different size than the viewport, and it's a technically valid console configuration, so apps should have been able to support it before.

Input is also tricky - VT doesn't let you express input with as much fidelity as a console app might be expecting, though this we're working on a solution for :)