Secondary Side Bar view contributions fallback to Explorer unexpectedly

[samii32]

Problem

I tried contributing a Webview to the secondarySideBar using the newly supported "viewsContainers.secondarySideBar" field as described in PR #247899.

However, even with correct activationEvents, ID matching, and version 1.97+, the view often falls back to the explorer container with this warning:

"View container 'ChatPanel' does not exist and all views registered to it will be added to 'Explorer'."

Expectation

Since secondarySideBar is officially supported now, I expect the Webview to be consistently displayed in the right sidebar without fallback.

Environment

• VSCode: 1.97.0
• Extension: test
• Package.json: using "viewsContainers.secondarySideBar" and correct view IDs

Request

Please ensure views registered to secondarySideBar are properly initialized without fallback, or document the current limitation if intended.

Thank you!