I apologize for the delay with the reply.
- enter a link in a cell that can have click eventListener?
Most probably this feature will be added in the future updates.
- add custom button or to override existing buttons action in toolbar and do something else.
Currently you may add your own custom buttons in the spreadsheet toolbar using the
spreadsheet.toolbar.data.add. Here you can find a tutorial:
- freeze Panes?
Unfortunately we have no recent plans do add such feature, but your request is sent to the dev team.