what is a bug imho: when using the 'preview gcode' from the menu, it works only if doing out from the prepare mode but not from the preview mode, what is very confusing.
Don't do what many do and confuse a "software bug" with a "perceived lack of functionality"
A "software bug" is an error, flaw, failure or fault in a computer program or system that causes it to produce an incorrect or unexpected result, or to behave in unintended ways....whereas "lack of functionality" is not an error, flaw or fault in a computer program...its the program not doing either what you want it to do or what you would expect it to do. There not being a convenient button to press is not a bug.....but a button not being there when there should be is a bug. Similarly, the "drag and drop" for gcode viewing may only have been built into the design view, and not built into the preview screen.
There not being clear documentation obviously doesn't help here!!