Hi, I submitted this as a bug report but the issue is caused by the browser having no access to key down and key up triggers when it is not in focus.
Have a look at this simple example and you'll see that, if a key is down when the browser becomes out of focus, the c2 engine never receives a key up trigger - so when you return to the game it continues as if the key is still being continually pressed, even though it is not!
When running in a browser tab this can be detected by the Page is Visible Browser condition, but if you run a game in a stand-alone browser- or NW window - then nothing gets triggerd that can be detected by c2. This is a real problem when running a game in NW... and I can't think of a robust work-around to detect when something else on the desktop has been put into focus.
I have tried using the Browser: On Suspended / On Resumed / Page is Visible conditions. However, none of these work when the browser/NW window is stand-alone, they only register when if page/tab/window is minimized...