Quality of syntax highlight / error checking way down?

Dan Royer, thanks for reaching out. I can see that you have the GitHub Copilot plugin installed. There have been recent reports from other users experiencing similar issues with syntax highlighting and error detection when this plugin is enabled.

• IDEA-372804: Compilation errors not shown while GitHub Copilot Chat is open
• IDEA-374360: Java syntax highlighting and error detection are stuck or slow when the Copilot window is open

As a temporary workaround, could you try disabling the GitHub Copilot plugin to see if the situation improves? This will help determine whether it's related.

Please let me know how it goes, and we'll see where to go next.

Hello,

Of course it's moments after I wrote the message - rubber duck style - that I remembered to try “repair IDE”.  that appears to have done it for now.  Thank you for your reply.

Glad to hear that the issue was resolved.

If the issue returns, especially with the GitHub Copilot plugin enabled, feel free to try disabling it temporarily as mentioned earlier, or reach back out. We’re happy to dig deeper if needed.

Let me know if there's anything else I can help with!

I can confirm the same issue - I struggle with intellij for last 2-3 months.
It breaks syntax check everywhere and makes IDE unusable. Clearing cache and indices helps only for a couple of minutes.
I was also thinking it may be connected with copilot, but honestly currently I even cannot disable it because my settings window stopped to open :)

Witold Kups, sorry to hear you're experiencing this issue. Please save all your changes and close all projects by selecting File | Close All Projects, or Close Project if only one is open. Then, return to the Welcome screen of your IDE, navigate to the Plugins tab, and under the Installed section, disable the GitHub Copilot plugin. After that, restart your IDE.

Let me know if this resolves the issue.

Some of us use Github copilot. Is that going to be fixed, or is the final answer that Github Copilot just breaks the IDE, therefore we have to choose one or the other?  For now, I have just downgraded to the latest version from 2024 and things work fine.

Ilnur Galimov 
1) I was not able to enable settings window. And I still cannot
2) I reinstalled the whole IDE. Twice, the second was with files running. Did not help
3) Then I realized a popup which was regarding another plugin, which showed me a way to open plugins in another way. Then I uninstalled copilot. Restarted. Did not help.

I am closing and opening all projects/cleaning cache/indices/reparing IDE from start to beginning. 
It just does not work, Ilnur. 

And really, I reinstalled the whole IDE twice. I will try later with EAP maybe…

Juliekanagy, thanks for raising this. Since GitHub Copilot is a third-party plugin, I recommend checking their official issue tracker for updates: https://github.com/microsoft/copilot-intellij-feedback/issues

It looks like a similar issue has already been reported here:
https://github.com/microsoft/copilot-intellij-feedback/issues/298

Hopefully the GitHub Copilot team will address the issue in an upcoming update.

Witold Kups, thank you for the update. I'm sorry to hear that disabling GitHub Copilot didn’t resolve the issue.

As a next step, we can try clearing the plugins directory. You can find instructions on locating it here.

Please let me know how it goes.

Ilnur Galimov , I removed the whole directory, which had intellij installed

For now I wipped all, and it worked. I wonder how long, maybe also performance issues will be solved for some time…

Witold Kups, if the issue re-occurs, please let me know.

• Ilnur Galimov so… I am letting you know. Repaired the IDE, did not help. Lags for last 3 days once again.
  And copilot is not installed. Linter shows errors in random places. see below
   

  

Witold Kups If repairing the IDE and clearing the cache couldn't mitigate the issue at all, I'd suggest you open a new ticket in YouTrack, and with below info collected.

1. IDE logs (entire archive): Help | Collect Logs and Diagnostics Data. We will look for exceptions and check your system environment settings.
2. A CPU snapshot that captures at least 20-30 seconds of IDE performance during the time the problems occur: Help | Diagnostic Tools | Start/Stop CPU Usage profiling
   To keep the readings clean and on point, start the profiling only when performance actually drops, and stop it right after you are done.