It probably works in many cases. To save yourself the trouble of cross-platform headaches I suggest you use Eto.Forms instead. We use this in Rhino as well for increasing amount of our GUI while we gradually replace to old, separate interface codebases and unify it all through one library.
Via Guides under the Advanced section you can get to Eto.Forms guides. See also our API section for access to the Eto.Forms documentation.
It is therefore possible for temporary interfaces or internal test windows, to use the Forms system.
This is great news, I have a lot of difficulties with Eto, so it will make my life easier in some cases.