Groovy registerToolWindow broken in 0.9.8 beta (ContentFactory double property access)

[dukky]

Description

Groovy plugins using registerToolWindow fail on LivePlugin 0.9.8 beta. Tested on GoLand 2025.2.5. Works fine in 0.9.7beta on GoLand 2025.2.1

Error

groovy.lang.MissingPropertyException: No such property: instance for class: com.intellij.ui.content.ContentFactoryImpl at liveplugin.implementation.ToolWindows.registerToolWindowIn(ToolWindows.groovy:103)

Root Cause

In src/plugin-api-groovy/liveplugin/implementation/ToolWindows.groovy on line 103, we have:

ContentFactory.getInstance().instance.createContent(...)

This is a double property access - getInstance() returns the ContentFactory, then .instance tries to access a non-existent property on it.

Kotlin API works

The Kotlin API (registerIdeToolWindow / registerProjectToolWindow) does not have this issue and works correctly.

Workaround for Groovy

I've been able to work around this in groovy by calling the IntelliJ APIs directly for now, which I think confirms the above issue being the cause.

Use the IntelliJ API directly instead of registerToolWindow:

import com.intellij.openapi.wm.RegisterToolWindowTask
import com.intellij.openapi.wm.ToolWindowAnchor
import com.intellij.openapi.wm.ToolWindowManager
import com.intellij.ui.content.ContentFactory

def twManager = ToolWindowManager.getInstance(project)
def existingTw = twManager.getToolWindow("My Tool Window")
if (existingTw != null) {
    twManager.unregisterToolWindow("My Tool Window")
}
def toolWindow = twManager.registerToolWindow(
    RegisterToolWindowTask.notClosable("My Tool Window", ToolWindowAnchor.RIGHT)
)
def content = ContentFactory.getInstance().createContent(
    myPanel, "", false
)
toolWindow.contentManager.addContent(content)

Environment

• LivePlugin: 0.9.8 beta
• IDE: GoLand 2025.2.5
• OS: macOS

[dkandalov]

Thank you for a very detailed issue report!
It will be fixed in the next plugin release.