Black screen in CLion while IntelliJ IDEA and PyCharm work normally

[Wanderer520]

Before submitting your bug report

• I've tried finding an answer on the Continue docs site
• I'm not able to find an open issue that reports the same bug
• I've seen the troubleshooting guide on the Continue Docs

Relevant environment info

- OS:Windows11
- Continue version:v1.0.67
- IDE version:CLion 2026.2.0.1
- Model:DeepSeek v4
- config:
  
name: Local Config
version: 1.0.0
schema: v1
rules:
  - When outputting ANY math equations or mathematical symbols, ALWAYS use
    double dollar signs like $$...$$ (EVEN FOR INLINE MATH). NEVER use single
    dollar signs ($...$), parentheses ((...)), or brackets ([...]).
models:
  - name: DeepSeek V4 Pro
    provider: openai
    apiBase: https://api.deepseek.com
    apiKey: xxxx
    model: deepseek-v4-pro
    capabilities:
      - tool_use
    defaultCompletionOptions:
      temperature: 0.2
      maxTokens: 8192
    requestOptions:
      timeout: 7200
      extraBodyProperties:
        thinking:
          type: enabled
        reasoning_effort: max
  - name: DeepSeek V4 Flash
    provider: openai
    apiBase: https://api.deepseek.com
    apiKey: xxxx
    model: deepseek-v4-flash
    defaultCompletionOptions:
      temperature: 0.2
      maxTokens: 8192
    requestOptions:
      timeout: 7200
      extraBodyProperties:
        thinking:
          type: enabled
        reasoning_effort: high

  
  OR link to agent in Continue hub:

Description

Continue opens with only the top toolbar visible.

The entire main panel is completely black and unresponsive.

There is no loading screen, no sign-in page, no model selector, and no error message.

To reproduce

• Reinstalled Continue
• Disabled all other third-party plugins
• Restarted CLion
• JCEF is enabled
• No relevant exceptions appear in idea.log

Log output

The exact same Continue configuration works correctly in:

- IntelliJ IDEA 2026.2
- PyCharm 2026.2

Only CLion shows this issue.
(Attach the black screen screenshot)

[Wanderer520]

Status: Resolved / Root cause found — this is NOT a Continue bug

I figured out the root cause of the black screen, and it turns out the issue was on my side (a JCEF setting + stale helper processes). Posting here in case it helps anyone else.

Environment

OS: Windows 11
IDE: CLion 2026.2.0.1 (JBR 25.0.3, JCEF 144.0.15-262-b37)
Plugins: Continue 1.0.67, Cline 1.1.64
Root cause The Continue (and Cline) panel is rendered by the IDE's embedded WebView (JCEF). Two things combined to cause the black screen:

I had manually disabled JCEF's out-of-process rendering via Help > Registry (the key ide.browser.jcef.out-of-process.enabled was set to false). In current JCEF versions, out-of-process rendering is required, so this broke the WebView entirely. This setting is persisted in options/ide.general.xml with source="USER".
Stale cef_server.exe helper processes were left running (they had not exited with the IDE) and were holding a lock on the JCEF cache directory (%LOCALAPPDATA%\JetBrains<Product>\jcef_cache). The IDE log showed: Failed to cleanup JCEF browser engine cache due to I/O error ... The process cannot access the file because it is being used by another process. This broke every JCEF-based plugin at once (Cline went black too, even though it had been fine before).
How I fixed it

Fully quit the IDE, then kill any leftover processes: taskkill /F /IM cef_server.exe
Delete the JCEF cache directory: %LOCALAPPDATA%\JetBrains\CLion2026.2\jcef_cache
Remove the manual registry override ide.browser.jcef.out-of-process.enabled from options/ide.general.xml (or set it back to true), so JCEF uses its default out-of-process rendering.
Restart the IDE — both Continue and Cline render normally again.
Note / possible improvement I had multiple JetBrains IDEs (IntelliJ IDEA, CLion, PyCharm) open simultaneously, all with Continue/Cline installed, which multiplied the number of JCEF helper processes and made the stale-process lock more likely. If Continue could detect a dead/stuck WebView and surface a clear message (instead of a silent black panel), that would have saved hours of debugging — worth considering.

Thanks to everyone who looked into this. Happy to provide any logs if needed.