Emit a selected even if there is only one item. Move data attribute set into the class and out of the renderer, it should not be a client responsibility.
Emit a selected even if there is only one item. Move data attribute set into the class and out of the renderer, it should not be a client responsibility.

jupyter/jupyterlab,eskirk/jupyterlab,charnpreetsingh185/jupyterlab,eskirk/jupyterlab,jupyter/jupyterlab,charnpreetsingh185/jupyterlab,jupyter/jupyterlab,charnpreetsingh185/jupyterlab,TypeFox/jupyterlab,eskirk/jupyterlab,eskirk/jupyterlab,jupyter/jupyterlab,TypeFox/jupyterlab,jupyter/jupyterlab,eskirk/jupyterlab,charnpreetsingh185/jupyterlab,charnpreetsingh185/jupyterlab,TypeFox/jupyterlab,TypeFox/jupyterlab,TypeFox/jupyterlab