#11078 – Paste option is enabled in Macromolecules mode when the clipboard is empty or contains not applicable content

[OnurKucukoz]

How the feature works? / How did you fix the issue?

The Paste option in the Macromolecules canvas context menu was enabled for any non-empty clipboard text, even when the content could not be converted and pasted.

This change validates clipboard content using the existing Indigo/KET conversion path before enabling Paste. Validation is performed without modifying the canvas, updating history, or displaying an error modal.

A regression test verifies that Paste is enabled for valid HELM content and becomes disabled after the clipboard is changed to invalid plain text.

After Fix

Invalid clipboard content disables the Paste option, while valid HELM content enables Paste and can be added to the canvas.

Issue.11078.-.Manuel.verification.mp4

Testing

Manually verified empty, invalid, HELM, and SMILES clipboard content
Playwright regression test passed
npm run check:autotests
TypeScript and ESLint checks passed
git diff --check

Fixes #11078

Check list

• unit-tests written
• e2e-tests written
• documentation updated
• PR name follows the pattern #1234 – issue name
• branch name doesn't contain '#'
• PR is linked with the issue
• base branch (master or release/xx) is correct
• task status changed to "Code review"
• reviewers are notified about the pull request