bug: heading overlay obscures text with Pandoc syntax conceal

Start by reproducing the heading.position = 'overlay' behavior with the shown lazy.nvim configuration and the pandoc filetype. Compare it with heading.position = 'inline', then isolate the effect of vim-pandoc-syntax conceal and vim-markdown in a minimal setup. Done means heading text remains visible for pandoc headings without changing the source contents.

Neovim version

0.12.0

Neovim distribution

Custom configuration using lazy.nvim

Operating system

Linux 6.17.0-40-generic

Terminal emulator / GUI

Kitty (TERM=xterm-kitty)

Describe the bug

In my setup, with the default heading.position = 'overlay', the numbered circle heading icons appear but the beginning of the heading text is obscured (approximately the first two letters). The file contents are intact. Setting heading.position = 'inline' avoids the problem.

This may be an interaction with the other Markdown plugins in my configuration rather than a standalone render-markdown bug: vim-pandoc sets the filetype of *.md to pandoc, vim-pandoc-syntax conceals ATX heading markers, and vim-markdown is also installed. The render-markdown plugin is configured to load for both markdown and pandoc filetypes. I have not isolated which of these is necessary to reproduce it.

Illustrative source text (the symptom was seen with headings at multiple levels in my files; this snippet is not a confirmed standalone reproducer):

# Heading sample
## Second heading
### Third heading

Observed: circular heading-number icons are drawn, but the first characters of heading text disappear from the displayed line. This is a visual problem only; the source text is unchanged. There are no plugin errors.

Expected behavior

Heading icons replace the Markdown marker without covering any heading text, including when the Markdown filetype is detected as pandoc.

Plugin configuration for reproduction

{
    'MeanderingProgrammer/render-markdown.nvim',
    ft = { 'markdown', 'pandoc' },
    dependencies = { 'nvim-treesitter/nvim-treesitter', 'nvim-tree/nvim-web-devicons' },
    opts = {}, -- heading.position defaults to 'overlay'
}

Local workaround: opts = { heading = { position = 'inline' } }.

Healthcheck output (:checkhealth render-markdown)

==============================================================================
render-markdown:                                                          7 ⚠️

render-markdown.nvim [versions] ~
- ✅ OK neovim >= 0.11
- ✅ OK tree-sitter ABI: 15
- ✅ OK plugin: 8.14.0

render-markdown.nvim [configuration] ~
- ✅ OK valid

render-markdown.nvim [tree-sitter markdown] ~
- ✅ OK parser: installed
- ✅ OK ABI: 15
- ✅ OK highlights: ~/.local/share/nvim/site/queries/markdown/highlights.scm
- ✅ OK highlighter: enabled

render-markdown.nvim [tree-sitter markdown_inline] ~
- ✅ OK parser: installed
- ✅ OK ABI: 15
- ✅ OK highlights: ~/.local/share/nvim/site/queries/markdown_inline/highlights.scm

render-markdown.nvim [tree-sitter html] ~
- ⚠️ WARNING parser: not installed
  - ADVICE:
    - disable html support to avoid this warning
      require("render-markdown").setup({
          html = { enabled = false },
      })
- ⚠️ WARNING ABI: unknown
  - ADVICE:
    - disable html support to avoid this warning
      require("render-markdown").setup({
          html = { enabled = false },
      })

render-markdown.nvim [tree-sitter latex] ~
- ⚠️ WARNING parser: not installed
  - ADVICE:
    - disable latex support to avoid this warning
      require("render-markdown").setup({
          latex = { enabled = false },
      })
- ⚠️ WARNING ABI: unknown
  - ADVICE:
    - disable latex support to avoid this warning
      require("render-markdown").setup({
          latex = { enabled = false },
      })

render-markdown.nvim [tree-sitter yaml] ~
- ⚠️ WARNING parser: not installed
  - ADVICE:
    - disable yaml support to avoid this warning
      require("render-markdown").setup({
          yaml = { enabled = false },
      })
- ⚠️ WARNING ABI: unknown
  - ADVICE:
    - disable yaml support to avoid this warning
      require("render-markdown").setup({
          yaml = { enabled = false },
      })

render-markdown.nvim [icons] ~
- ✅ OK using: nvim-web-devicons

render-markdown.nvim [latex] ~
- ⚠️ WARNING none installed: { "utftex", "latex2text" }
  - ADVICE:
    - disable latex support to avoid this warning
      require("render-markdown").setup({
          latex = { enabled = false },
      })

render-markdown.nvim [conflicts] ~
- ✅ OK headlines: not installed
- ✅ OK markview: not installed
- ✅ OK obsidian: not installed

Plugin error log

N/A

Additional information

Installed render-markdown version 8.14.0 (640a3ec), matching upstream HEAD when checked. markdown and markdown_inline parsers are present. I have not run :TSUpdate as part of this report, and cannot yet claim a clean/minimal configuration reproduces it. If this is due to conflicting Pandoc syntax conceal, guidance on compatibility or an appropriate fallback would be helpful.