feat: allow copy/paste between browser windows

[comlit]

added ability to copy and paste bpmn elemtents between browser window or different applications using the systems clipboard

implementation based on this

closes #1709

[barmac]

The CI is failing right now. Can you have a look?

[comlit]

yes we looked at the failing tests and identified it happening because of issues with asynchronous code in testing, which did not occur while testing locally. We are on it👍

[barmac]

Hi,
I've tried this out, and it worked fine for a basic case. However, once we dig deeper, there are the following issues:

• The module logs an error for any text in the clipboard which does not meet the expectations.
• There are even uncaught errors in case a proper JSON was present in the clipboard. After that, the feature stops to work.
• Naturally, you cannot copy and paste elements with custom moddle extensions to an instance without it. This is expected, but we could handle this gracefully (e.g. strip extensions).
• Obviously, the browser asks for a permission to use the clipboard. I think this should happen only when one tries to copy or paste, and not immediately when canvas is focussed.
• There is a problem with serialization when I try to paste an element with a linked root element (receive task with messageRef): Failed to parse clipboard contents: Cannot read properties of null (reading '$type')

Screen.Recording.2025-06-25.at.16.24.16.mov

I think this should happen only when one tries to copy or paste, and not immediately when canvas is focussed.

This requirement might be difficult to implement given the asynchronous nature of the API. This could be a reason to make the feature optional.

[barmac]

Suggestion: Look up how excalidraw handles cross-browser copy and paste. You can use an existing copy-to-image service, and add descriptor embedding to it.

[barmac]

Or easier: Adopt the pattern of setting type on the text contents, and ignore anything that does not match the expectation

[barmac]

Cf. the comments above.

[comlit]

Hey, thank you very much for your feedback. Unfortunatly the submission deadline for the informaticup (which was our motivation to tackle this issue in the first place) ends tomorrow. This means that we as a team unfortunatly have to focus on other university work. Nevertheless we would like to see this feature merged and will try to tackle the requested changes in our own time.

[barmac]

All right! Thanks for notice.