[UI bug] Context rendering."Pencil Icon" Occasionally Disappears from Model Chat Bubbles, Preventing Message Editing

Google AI Studio
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Issue Description

· Environment: Web, Browser: [Chrome], Android OS

· Trigger Scenario: After a normal conversation, the model’s chat bubble occasionally fails to display the “pencil” icon.

· Duration: Observed over the last two to three days.

· Symptoms:

1. The “pencil icon” (edit button) in the upper left corner disappears completely.

2. Tapping the message bubble with a finger does not reveal the icon.

3. Other normal messages still display the pencil icon and remain clickable.

4. The missing icon does not reappear after refreshing the webpage.

5. Switching to Firefox browser also fails to display the “pencil” icon.

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IMG_20260410_165408
IMG_20260410_1654081500×1474 85.7 KB

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Issue Summary:
In Google AI Studio, when a conversation reaches a high token count (approx. 350k+), the “Edit” button (pencil icon) on the model’s message bubble completely disappears and cannot be restored by refreshing.

Detailed Environment:
Platform: Exists on both Android (Chrome/Firefox) and PC (Chrome).
Trigger Condition: Long conversation context. The issue starts appearing frequently especially when the token count reaches around 359,365.
Reproducibility: Highly reproducible in long conversations; normal in new chats (New Chat).
Model: gemini-3.1-pro-preview

Symptom Description:

  1. The “Edit” button (aria-label=“Edit”) in the upper right corner of the message bubble completely disappears, becoming invisible and unclickable.
  2. Refreshing the web page, changing browsers, or enabling desktop mode cannot bring the icon back.
  3. This issue is “irreversible”; once the bubble icon disappears, it seems to be permanently disabled within the current session.

Technical Detail Investigation (F12):
Observation via Chrome Developer Tools reveals: under normal circumstances, the container should include a with aria-label=“Edit”.
However, when the failure occurs, this tag is completely removed (Destroyed/Removed) from the DOM tree, rather than simply being hidden via CSS (display: none).
This is suspected to be the Angular framework incorrectly determining the isEditable state of the message when handling long list rendering (Virtual Scroll) or state synchronization.

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This image is normal.

QQ_1775885303777
QQ_17758853037771351×1499 276 KB

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This image shows a missing “pencil” icon.

9365445a-f787-4791-b19d-7cd5edea57c5
9365445a-f787-4791-b19d-7cd5edea57c51164×1407 184 KB

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This appears to be a regression. Previously, the Edit icon functioned perfectly even with context lengths up to 1M tokens. However, following the recent UI updates, the icon now consistently disappears once the context reaches approximately 360k tokens.
I found a strong correlation(my guess)—the Edit icon only disappears on message bubbles that contain exceptionally long “Thoughts” (Chain of Thought) sections. It seems the rendering of massive collapsible “Thoughts” components is interfering with the rendering of the message action toolbar (the Edit button).

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I can confirm this happens to me too, sometimes the pencil is missing. Although I do not really use it, it adds up to the long list of simple to fix but somehow still not fixed bugs in this platform

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[Mobile App Bug] When editing long text, the bottom of the editor cannot scroll, blocking part of the content.

Oh yeah, there’s this similar bug too. The web UI’s been changing a lot lately. I think their main focus right now is probably just updating the UI.