I submitted a request on Github but I felt that this feature request was also worth mentioning here:
By default, the Canvas component is sized so that it fits a portrait screen. However, it’s incredibly difficult to make a game in landscape. In order to do this, you need to change the app screen orientation to landscape and, using trial and error, adjust the width and height of the Canvas stage until it fits the screen perfectly - which is almost impossible to do.
Just as you can choose your phone orientation when creating new screens (landscape, portrait, auto), you should be able to choose the orientation of a Canvas stage. Adding this feature would allow users to easily create games with both portrait and landscape orientations.