In a fullscreen plugin on ChatGPT mobile, tapping the composer briefly opens the chat sheet from the bottom. It immediately closes, reopens, then expands to the top, leaving the plugin out of fullscreen.
During the first opening, the inline card shows a gray loading placeholder. When the sheet reopens, the card appears loaded. This suggests an issue related to new iframe loading, but the cause is unconfirmed.
About two weeks ago, opening composer chat showed an inline version of the plugin that could itself launch another fullscreen view. This suggests the chat sheet renders a separate iframe.
Expected: Composer chat opens while the plugin remains fullscreen.
I am reproducing this on both iOS and Android, using a minimal standalone MCP App built specifically to isolate the issue.
Devices and ChatGPT app versions:
- iPhone 13 mini: ChatGPT 1.2026.237 (33230022603) - iOS 26.6.1
- Samsung Galaxy, S21+: ChatGPT 1.2026.216 - Android 15
The demo contains five hard-coded true/false questions, local grading, and no application backend beyond the MCP server serving the widget.
On iOS: Opening ChatGPT’s composer, even without typing or sending anything, causes the chat sheet to open, close, reopen, and eventually leave the quiz inline. The same happens after tapping “Ask ChatGPT why - button that I implemented so I don’t have to type all the time” and expanding the explanation preview.
On Android: “Ask ChatGPT why” produces an explanation in a small bubble that I can scroll within. However, tapping to expand it takes the quiz out of fullscreen and back to inline. I don’t observe the same repeated opening/closing animation as on iOS.
The shared problem is that expanding the chat/explanation does not preserve the fullscreen quiz for returning to it.
Implementation details:
- Standard MCP Apps
app.sendMessage.
- Also tested
window.openai.sendFollowUpMessage({ prompt, scrollToBottom: false }) on iOS; the issue persists.
- No
setWidgetState, updateModelContext, app-initiated close/teardown, content hiding, or parent-DOM manipulation.
- No automatic fullscreen reopening after composer interactions.
- SDK automatic resizing and browser-local answer storage are enabled, so a sizing interaction hasn’t been ruled out.
The iOS log shows the host switching to inline without a corresponding display request from our code:
18:14:02.167 APP message standard; question 1; mode fullscreen
18:14:02.172 message accepted; NO display request
18:14:11.930 HOST context: mode inline
The captured iframe’s mount ID remains unchanged. The same demo’s explanation-and-continue flow worked in desktop ChatGPT.
This appears related to mobile fullscreen/chat-sheet handling, but we haven’t confirmed the root cause. Could OpenAI clarify whether this is expected behavior or a known issue, and whether there is a supported way to return from the expanded conversation to the same fullscreen widget?
I can provide a minimal reproduction and diagnostic logs.