Hmmm! I'm afraid that you have made a mistake. I've tried in my own project and works OK.
- My project has a 1024 x 768 resolution
- My scene has a 1300 x 768 resolution
- I've changed the game resolution in Project Manager / Startup Settings/ Resolution to 800 x 600 (are you changed the resolution here?)
- I've changed the scene resolution in the Layer properties option in SceneEdit to 1300 x 600
And the scene works ok with 800 x 600 resolution, as the scene has 1300 pixels width, the layer scroll horizontally. As the project and the scene has 600 pixels height, the bitmap has clipped to 600 pixels.
Review the resolution in Project Manager and SceneEdit, becouse don't need other options.
Note that the game resolution is changed in the Project Manager, the scenes can be less, equal or greater than the game resolution, if the size of the scene is greater than the game resolution, WME scrolls the scene when the actor moves through this one.