Add scroll-to-bottom button for terminal auto-scroll control

[Copilot]

Users couldn't review serial terminal history while new data arrived because auto-scroll always forced viewport to bottom.

Changes

WebUI Commands Panel (ESP3D-WEBUI v1.14 → FluidNC)

• Added floating scroll-to-bottom button that appears when user scrolls up
• Auto-scroll now pauses when scrolling up, resumes on button click or manual scroll to bottom
• Button dynamically injected via JavaScript at runtime

Implementation

• Injected JavaScript at end of index.html.gz that overrides Monitor_check_autoscroll()
• Adds scroll event listener to cmd_content element to detect user scrolling
• Dynamically creates scroll-to-bottom button with inline styles (blue circle, double-chevron icon)
• Button positioned bottom-right with absolute positioning (z-index 100)
• No changes to HTML structure - purely runtime JavaScript injection

Behavior

// Pauses when user scrolls up
if (Monitor_last_scroll_pos > element.scrollTop && getChecked("monitor_enable_autoscroll") !== "false") {
    Monitor_autoscroll_paused = true;
    Monitor_show_scroll_button();
}

// Resumes when within 5px of bottom OR button clicked
if (isAtBottom && Monitor_autoscroll_paused) {
    Monitor_autoscroll_paused = false;
    Monitor_hide_scroll_button();
}

Version Compatibility Fix: Initial implementation incorrectly used ESP3D-WEBUI v3.0 (Preact-based) instead of v1.14 that FluidNC uses. Fixed by restoring original v1.14 WebUI and applying modifications via JavaScript injection. This approach ensures full compatibility with existing FluidNC infrastructure without breaking changes.

Modified index.html.gz with injected smart auto-scroll JavaScript (+1.6KB). Existing auto-scroll toggle remains functional.

• Fixes [Feature Request] No Auto-Scroll of Serial output when not at the bottom #504

Original prompt

---

This section details on the original issue you should resolve

<issue_title>[Feature Request] Serial Keeps scrolling</issue_title>
<issue_description>I would like to go through the serial output while it is printing new stuff. But the auto-scroll prevents this.

The feature request:

• add a button to scroll to the bottom
• when at the bottom of the serial output, follow the printing
• when not the the bottom of the serial output, stay in that location.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes [Feature Request] No Auto-Scroll of Serial output when not at the bottom #504

---

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[atari-zero]

@MaslowBot /build

[github-actions]

🤖 Firmware Compilation Complete 🤖

✅ Successfully compiled FluidNC firmware for ESP32-S3 (wifi_s3 environment)

Build Details:

• Commit: 9ec131009be1ab2de8f0f35f182171314ab47b6d
• Version: v1.14-10-g9ec13100
• Environment: wifi_s3
• Firmware size: 1.89 MB
• Flash usage: 1.89 MB (64.4%)
• RAM usage: 135.9 KB (42.5%)
• Build time: ~2 minutes

Download:
The firmware package (containing firmware.bin and installation instructions) has been uploaded as a build artifact named "firmware-package" and can be downloaded from the Actions tab.

To test this release please:
[] Try running calibration with a fresh maslow.yaml file
[] Test jogging the machine to see that movements are normal
[] Try running a simple gcode file

This comment was automatically generated in response to a build request comment.

[atari-zero]

@MaslowBot This does not work. Floating scroll-to-bottom button does not appear and the log scrolls down every time new line prints regardless of how far up it was scrolled manually

[MaslowBot]

@copilot-swe-agent

User @atari-zero mentioned @MaslowBot with the following request:

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@MaslowBot This does not work. Floating scroll-to-bottom button does not appear and the log scrolls down every time new line prints regardless of how far up it was scrolled manually

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

This comment was automatically relayed by MaslowBot so that @copilot-swe-agent can respond to the request.

[Copilot]

@MaslowBot This does not work. Floating scroll-to-bottom button does not appear and the log scrolls down every time new line prints regardless of how far up it was scrolled manually

I apologize for the error. I built the WebUI from ESP3D-WEBUI v3.0 instead of the v1.14/v2.1 that FluidNC uses, resulting in an incompatible WebUI that's missing panels and functionality.

I'm restoring the original WebUI and working on a proper fix. The modifications need to be made to the v1.14 codebase, not v3.0.

[atari-zero]

@MaslowBot /build

[github-actions]

🤖 Firmware Compilation Complete 🤖

✅ Successfully compiled FluidNC firmware for ESP32-S3 (wifi_s3 environment)

Build Details:

• Commit: 010a7f9f7b0dc4c282218b649c73a12a28d0d323
• Version: v1.14-12-g010a7f9f
• Environment: wifi_s3
• Firmware size: 1.89 MB
• Flash usage: 1.89 MB (64.4%)
• RAM usage: 135.9 KB (42.5%)
• Build time: ~2 minutes

Download:
The firmware package (containing firmware.bin and installation instructions) has been uploaded as a build artifact named "firmware-package" and can be downloaded from the Actions tab.

To test this release please:
[] Try running calibration with a fresh maslow.yaml file
[] Test jogging the machine to see that movements are normal
[] Try running a simple gcode file

This comment was automatically generated in response to a build request comment.

[davidelang]

is this actually changing the UI code? I think this needs to be submitted in that UI repo. David Lang