Re: ‘x’ not working in the cell and the ChoiceList editor in the column configuration, that’s strange. Is this only true for ChoiceLists or also for Choices? How about Reference Lists?
Do you have any browser extensions that could be interfering?
Re: editing a choice, there is currently no way to do it, but it is something we’d like to implement. The feature was requested here: Feature Request - Editable Choices