SelectableText in the demo is conflict from the source

[renntbenrennt]

Hi there, we have a project in need of the function this package provided, but I failed to run the example, could you spend some time to have a look?

Thanks in advance.

So, you can see the issue from the screenshot:

Like what it says, but which source should we use?

Besides, no matter which source I choose, there will be errors like:

How to resolve these?

Thanks!

PS, I really think that as the author of the package, the example should be easier to begin with...