[bug]: Code block syntax highlighting breaks completely upon pasting code (only works when manually typed)
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Since Aug 19, 2026.
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- TypeScript
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Description
Is there an existing issue for this?
- I have searched the existing issues
Current behavior
The rich-text editor actually contains functional syntax highlighting token rules for PowerShell (as verified when writing single commands line-by-line). However, the editor completely fails to parse and tokenize text content when it is introduced via a Copy-Paste action.
- When a script is pasted into an existing ````powershell` block, the text remains entirely plain white text.
- When the exact same syntax components (variables, string literals, arguments) are typed in manually, the editor instantly maps the CSS highlighting rules correctly.
This indicates a severe bug in the editor's Paste-Handler extension, which suppresses tokenization/re-rendering of the code block nodes upon clipboard input injection.
Steps to reproduce
- Create a PowerShell code block inside an issue description or page using
```powershell - Scenario A (Manual Input): Type a basic snippet by hand (e.g.,
$ApiKey = $env:OPENAI_API_KEY).
-> Result: Variables and values get highlighted instantly. - Scenario B (Paste Input): Copy a multi-line script from an external editor (VS Code, Notepad, etc.) and press Ctrl+V to paste it into the same block.
-> Result: The pasted content drops all syntax formatting and renders completely plain/white.
Expected Behavior
Injecting clipboard data into a language-specific Fenced Code Block node must trigger the underlying lowlight/Prism lexer to parse the block immediately, ensuring that pasted documentation remains fully highlighted and readable.
Environment
- Component: packages/editor or apps/web (Tiptap Paste Handler/Lowlight Node extension)
- Impacted Scope: Multi-line technical documentation snippets.
Environment
Production
Browser
Mozilla Firefox
Variant
Self-hosted
Version
v1.4.1
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