I'd like to have a plug-in that implements indeterminate checkboxes (boxes where the parent shows 3 states—all nested children unchecked, some checked, or all checked). The parent boxes with partially checked children have a "-" in the box. The only app I've used after trying numerous note-taking and outlining apps that offer checkboxes that does it "right" is OmniOutliner. I understand this is not a feature all users want so I'm not requesting it be a core feature unless it's optional.
However, developing a plug-in is way beyond my skill level and while ChatGPT was quite confident it could do it for me, it failed miserably. It did, however, develop a simple HTML file with JavaScript file that implements the functionality to demonstrate what I'm looking for. It also has collapsible parents that also allow collapse or expand all nested, and it remembers that state.
Can any plug-in guru turn this into one for me? Thanks.
Indeterminate Check Boxes.zip (3.1 KB)