Possible Plugin Manager bug: Duplicate plugin entries after "Install Plugin from Disk" until IDE restart

IntelliJ Platform
1

I’m seeing some unexpected behavior when installing a plugin from a ZIP file using Install Plugin from Disk, and I’m wondering if this is expected behavior or a bug in the Plugin Manager UI.

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Environment

  • IntelliJ IDEA 2026.2 and 2026.1

  • macOS

Steps to reproduce

  1. Download a plugin ZIP from JetBrains Marketplace.

  2. Open Plugins → Install Plugin from Disk.

  3. Select the ZIP (the plugin is not already installed).

  4. Observe the Installed plugins list before restarting the IDE.

Observed behavior
Immediately after installation, the Installed list sometimes shows duplicate entries (e.g. Liberty Tools, LSP4IJ, or both). The duplicates have the same version and appear identical.

After restarting the IDE, the duplicates disappear and the Installed list is correct.

Is this expected behavior, or is it a known Plugin Manager UI issue?

2

We have the following issue on YouTrack that sounds like it’s the behavior you describe:

If it’s indeed your bug, it’s best to follow this ticket.

A quick search suggests that the bug is very likely a race in the Plugin Manager Installed UI update path after Installing a Plugin from Disk.
pluginInstalledFromDisk() schedules the update on an IO coroutine, but the code it calls mutates Swing UI state and shared ArrayLists that are effectively EDT-only / not thread-safe. If the install produces multiple callbacks (main plugin + dependencies), those updates can run concurrently, corrupting the in-memory “Installed” list and causing duplicates until restart.