[Bug]: Text box and text rendering fails when rendered over an image

[dkritarth]

Description

When an image in the timeline is scrolled underneath the composer overlay docked at the bottom of the timeline, text inside the input box suffers from severe contrast and legibility degradation, appearing washed out, garbled, or unreadable against the underlying image content.

Steps to Reproduce

1. In a thread, have an image (such as an image pasted in the conversation or generated by an agent) scrolled down towards the bottom of the chat view.
2. Allow the image to scroll underneath the docked composer / prompt overlay.
3. Type text or observe placeholder / prompt text in the input box over the translucent glass backdrop.
4. Observe that the text rendering contrasts poorly or becomes difficult to read/distorted over high-contrast or textured image backgrounds.

Expected Behavior

Text in the composer input area should maintain strong legibility and clear contrast regardless of what is scrolled beneath the composer (e.g. through adequate opacity, contrast enforcement, or appropriate backdrop shielding).

Actual Behavior

Text rendered over the image area loses contrast and clarity, making glyphs difficult to distinguish and appearing washed out / partially obscured against image features.

Environment

• T3 Code version: v0.0.43-nightly.20260923.2150
• Platform: Desktop / Web app
• OS: Ubuntu 24.04 LTS (Linux x86_64)

Screenshot

Additional Context

The composer uses a translucent backdrop layer (backdrop-filter: blur(12px) saturate(1.14) over ~80% surface background). When complex, high-contrast, or transparent/alpha image content scrolls beneath this glass layer, the text rendering layer above it suffers from legibility issues, particularly on Linux / Chromium environments.

[juliusmarminge]

Triage

Thanks for the report. There is not enough here to confirm a text-rendering bug, so this needs a real capture and environment before it can be treated as one.

The screenshot on the issue 404s. Its asset id is two ids joined together (6dc7a4f9-fe5c-47c1-ae05-8411877bb87c and affa399a-bceb-4319-a86d-6394ab5b7cfb), and neither URL exists. The follow-up image is written as attachment:t3code-text-over-image-bug.png, which GitHub did not upload. Version, surface, and OS are still the placeholders ("latest", "Web / Desktop / Mobile", "specify"). The symptom list covers garbled glyphs, missing glyphs, wrong color, and clipping at once, so it is not clear which of those you actually saw.

Once a thread has messages, the composer is an overlay docked on the bottom of the timeline. Its shell is already isolate. The glass behind the prompt is a translucent backdrop (about 80% surface color, 12px blur, saturate(1.14)), and the prompt is painted above that layer. An image scrolled underneath the composer will show through the glass. That is the intended look, not a missing stacking fix. Message text sits in normal markdown flow next to images; it is not drawn on top of them.

Adding isolation: isolate would not change the composer. There is a separate open report, #10335, about Windows Chromium shifting unrelated text when a menu with a saturated backdrop-filter opens. This report does not describe that interaction, and the two should not be treated as the same bug without a capture.

Please reply with:

1. A screenshot or short recording uploaded by dragging the file into the comment.
2. The version (t3 --version, or the desktop About version), OS, and which surface this is: desktop app, app.t3.codes, a local t3 serve page, or mobile.
3. One concrete failure — garbled glyphs, missing glyphs, wrong color, or clipping — and whether it is the prompt, a message, or a label on a thumbnail.
4. Whether it happens only while an image is scrolled underneath the composer, or also when the image is simply in the thread above it.

[dkritarth]

Here is the captured screenshot and environment details:

Screenshot

1. Screenshot: Attached above (and updated in the main issue description).
2. Environment & Surface:
   • Version: t3 v0.0.43-nightly.20260923.2150
   • OS: Ubuntu 24.04.4 LTS (Linux x86_64)
   • Surface: Desktop / Web app
3. Concrete failure: When high-contrast/patterned image content sits behind the translucent composer backdrop, text contrast and glyph clarity degrade significantly—the input text/placeholder blends into underlying dark/light patterns through the glass surface, making characters difficult to read and track.
4. Occurrence: This happens specifically when the image is scrolled underneath the docked composer overlay (it does not affect message text higher up in normal markdown flow).