Hello.
When you use new canvas object and set it to use screen space - worldspace instead of overlay, buttons wont register any kind of events (hover or click).
Its easily fixable by creating a new scene and copying default unity camera from there to scene containing 2dtoolkit camera.
Its easily reproducable, could you maybe fix it?
Screen space overlay works fine (I think) but there are moments where it would be very helpfull to display UI over normal worldspace.