Make mindmap workspace working properly in browser

[SmartWolf1220]

Pull Request type

Please check the type of change your PR introduces:

• [x] Bugfix
• [x] Feature
• [ ] Code style update (formatting, renaming)
• [ ] Refactoring (no functional changes, no API changes)
• [ ] Build-related changes
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• [ ] Other (please describe):

Implement mindmap workspace and make it working properly in browser.

[SmartWolf1220]

Ok, I will fix it and let you know when it's done.

[SmartWolf1220]

@dacoaster , I have updated the code. Please check and let me know.