allow referencing other properties in the update metadata button action

[mProjectsCode]

[mProjectsCode]

currently only possible by utilizing JavaScript, either via a button action that can run JS (and then use the MB API) or crating the button dynamically similar to the advanced examples in the docs

[mProjectsCode]

implemented with a getMetadata(bindTarget) function that you can pass a bind target sting.

Example:

label: "Add count to count2"
hidden: false
style: default
actions:
  - type: updateMetadata
    bindTarget: count2
    evaluate: true
    value: "x + getMetadata('count')"