The "openai/widgetPrefersBorder" resource metadata causes intermittent issues when in fullscreen.

[AaronV-T]

When an MCP resource for a ChatGPT app has the openai/widgetPrefersBorder metadata set to true, it causes an app embedded in ChatGPT to randomly have an issue after going into fullscreen mode in which the app is not clickable in any area that is outside the exact area of the app when it was in inline mode. When right clicking in one of these unclickable areas of the app and selecting "Inspect Element", it selects the highest ancestor iframe of the app.

This issue is reproducible by editing pizzaz_server_node/src/server.ts to set openai/widgetPrefersBorder to true:

function widgetDescriptorMeta(widget: PizzazWidget) {
  return {
    "openai/outputTemplate": widget.templateUri,
    "openai/toolInvocation/invoking": widget.invoking,
    "openai/toolInvocation/invoked": widget.invoked,
    "openai/widgetAccessible": true,
    "openai/widgetPrefersBorder": true,
  } as const;
}

The pizzaz map widget will normally never encounter this issue, but with the change above the issue is reproducible in the pizzaz map widget (it sometimes takes a few page reloads to reproduce it):

ChatGPT.App.fullscreen.bug.mp4

[AaronV-T]

The OpenAI developer documentation previously had a section for the openai/widgetPrefersBorder resource metadata, but now that metadata seems to be deprecated and not do anything anymore. Though there are still references to that metadata in some code snippets on https://developers.openai.com/apps-sdk/build/mcp-server