Wide Markdown tables lack visible horizontal scrollbars

[Zeraphim]

Body

Reproduction steps

1. Start Zed.
2. Open a Markdown file containing a table whose columns are wider than the available preview area, for example:

| Package | Description | Documentation |
| --- | --- | --- |
| `example-package-with-a-long-name` | This description is deliberately long enough to exceed the width of a documentation popover or narrow Markdown preview. | `https://example.com/documentation/with/a/long/path` |

3. Open the Markdown preview or display the table in a documentation popover.
4. Try to discover and navigate the table's horizontally overflowing content.

Current vs. Expected behavior

Current behavior: After #61698, wide Markdown tables can be scrolled horizontally, but no horizontal scrollbar is shown. This makes the overflow difficult to discover and difficult to navigate without a trackpad or another horizontal scrolling input.

Expected behavior: A wide Markdown table should use Zed's standard horizontal scrollbar when its content overflows. Tables that fit within the available width should not show an unnecessary scrollbar.

This is a table-specific follow-up to #61698 and is related to the broader scrollbar tracking issue #15324.

Zed version and system specs

Zed: v1.12.1
OS: macOS 26.5
Chip: Apple M5
Memory: 24 GiB
Architecture: aarch64

Attach Zed log file

Not applicable. This is a rendering and interaction issue and does not produce a log error.

Relevant Zed settings

None.

Relevant Keymap

None.

(for AI issues) Model provider details

Not applicable.

If you are using WSL on Windows, what flavor of Linux are you using?

Not applicable; this was reproduced on macOS.

[Zeraphim]

Related PR #61745

[JosephTLyons]

Horizontal scrollbars for wide Markdown tables have shipped in Zed Stable v1.16.1!

Thanks for implementing this, @Zeraphim! :)