I am posting this here to help others who might be having the same problem as I wasn’t getting any results when searching for the error message.
When adding a new page in the panel the modal would appear, I would fill it in, but when i pressed return or clicked the Add button a Javascript alert would appear with the following error:
Call to a member function bindTo() on string in file: /Users/sam/development/balham/kirby/kirby.php on line: 768
Eventually I narrowed down the source of the problem to the auto publish plugin.
Big thanks to @oliverschneider who patched it and submitted a pull request. Though the plugin repo has not seen much love for a while so it might not make it to a release. But you can get the patch from @oliverschneider’s repo if it is a plugin you use.