diff --git a/lua/snacks/gh/actions.lua b/lua/snacks/gh/actions.lua
index 74f1471c..f0569dcc 100644
--- a/lua/snacks/gh/actions.lua
+++ b/lua/snacks/gh/actions.lua
@@ -28,6 +28,24 @@ local M = {}
 ---@field type? "pr" | "issue"
 ---@field enabled? fun(item: snacks.picker.gh.Item): boolean
 
+---@param item snacks.picker.gh.Item
+---@param ctx snacks.gh.action.ctx
+local function update_main(item, ctx)
+  local gh = { repo = item.repo, number = item.number, type = item.type }
+  if ctx.main and vim.api.nvim_win_is_valid(ctx.main) then
+    local buf = vim.api.nvim_win_get_buf(ctx.main)
+    if vim.deep_equal(vim.b[buf].snacks_gh or {}, gh) then
+      return ctx.main, buf
+    end
+  end
+  local win = vim.api.nvim_get_current_win()
+  local buf = vim.api.nvim_win_get_buf(win)
+  if vim.deep_equal(vim.b[buf].snacks_gh or {}, gh) then
+    ctx.main = win
+    return ctx.main, buf
+  end
+end
+
 ---@class snacks.gh.actions: {[string]:snacks.gh.Action}
 M.actions = setmetatable({}, {
   __index = function(_, key)
@@ -80,7 +98,7 @@ M.actions.gh_actions = {
     if ctx.action and ctx.action.cmd then
       return Snacks.picker.actions.jump(ctx.picker, item, ctx.action)
     end
-    ctx.main = ctx.main or ctx.picker and ctx.picker.main or nil
+    update_main(item, ctx)
     local actions = M.get_actions(item)
     actions.gh_actions = nil -- remove this action
     actions.gh_perform_action = nil -- remove this action
@@ -103,9 +121,10 @@ M.actions.gh_actions = {
         end
         ctx.action = action
         if ctx.picker then
+          ctx.picker.visual = ctx.picker.visual or picker.visual or nil
           ctx.picker:focus()
         end
-        ctx.main = ctx.main or picker and picker.main or nil
+        update_main(item, ctx)
         it.action.action(item, ctx)
         picker:close()
       end,
@@ -242,25 +261,55 @@ M.actions.gh_comment = {
   title = "Comment on {type} #{number}",
   icon = " ",
   action = function(item, ctx)
-    item = item.gh_item or item -- unwrap from
-    local current_win = vim.api.nvim_get_current_win()
-    local win = vim.w[current_win].snacks_picker_preview and current_win or ctx.main or current_win
-    local buf = vim.api.nvim_win_get_buf(win)
-
     local action = vim.deepcopy(M.cli_actions.gh_comment)
-    if vim.b[buf].snacks_meta then
-      local lino = vim.api.nvim_win_get_cursor(win)[1]
-      local meta = vim.b[buf].snacks_meta or {}
-      for _, c in ipairs(meta) do
-        if c.line == lino and c.comment_id then
+    local win, buf = update_main(item, ctx)
+    if win and buf then
+      local meta = Snacks.picker.highlight.meta(buf)
+      if meta then
+        ---@type {comment_id?: number, diff?: snacks.diff.Meta}?
+        local m = meta[vim.api.nvim_win_get_cursor(win)[1]]
+        if m and m.comment_id then
           action.title = "Reply to comment on {type} #{number}"
+          action.api = {
+            endpoint = "/repos/{repo}/pulls/{number}/comments",
+            input = { in_reply_to = m.comment_id },
+          }
+        elseif m and m.diff then
+          local visual = ctx.picker and ctx.picker.visual or Snacks.picker.util.visual()
+          visual = visual and visual.buf == buf and visual or nil
+          local line = m.diff.line ---@type number
+          local start_line ---@type number?
+          if visual then
+            local line_diff = vim.tbl_get(meta, visual.end_pos[1], "diff") or m.diff --[[@as {file: string, line: number, side: string}]]
+            local start_diff = vim.tbl_get(meta, visual.pos[1], "diff") or m.diff --[[@as {file: string, line: number, side: string}]]
+            if line_diff.file ~= start_diff.file then
+              Snacks.notify.error("Cannot add comment: visual selection spans multiple files")
+              return
+            end
+            line, start_line = line_diff.line, start_diff.line
+            start_line, line = math.min(start_line or line, line), math.max(start_line or line, line)
+          end
+          start_line = start_line ~= line and start_line or nil
+          if start_line then
+            action.title = ("Comment on lines %s%d to %s%d"):format(
+              m.diff.side:sub(1, 1):upper(),
+              start_line or line,
+              m.diff.side:sub(1, 1):upper(),
+              line
+            )
+          else
+            action.title = ("Comment on line %s%d"):format(m.diff.side:sub(1, 1):upper(), line)
+          end
           action.api = {
             endpoint = "/repos/{repo}/pulls/{number}/comments",
             input = {
-              in_reply_to = c.comment_id,
+              commit_id = item.headRefOid, -- or item.headCommit.oid depending on your data structure
+              path = m.diff.file,
+              side = m.diff.side:upper(), -- "RIGHT" or "LEFT" (uppercase)
+              line = line,
+              start_line = start_line,
             },
           }
-          break
         end
       end
     end
diff --git a/lua/snacks/gh/api.lua b/lua/snacks/gh/api.lua
index e44758e4..5c277ee2 100644
--- a/lua/snacks/gh/api.lua
+++ b/lua/snacks/gh/api.lua
@@ -56,6 +56,7 @@ local config = {
       "baseRefName",
       "deletions",
       "headRefName",
+      "headRefOid",
       "mergedAt",
       "statusCheckRollup",
       "reviews",
diff --git a/lua/snacks/gh/buf.lua b/lua/snacks/gh/buf.lua
index e92f467d..e6617f32 100644
--- a/lua/snacks/gh/buf.lua
+++ b/lua/snacks/gh/buf.lua
@@ -32,7 +32,7 @@ function M.new(buf, item)
   vim.b[buf].snacks_gh = {
     repo = item.repo,
     type = item.type,
-    number = item.number,
+    number = tonumber(item.number) or item.number,
   }
   self:bo()
   self:wo()
diff --git a/lua/snacks/gh/types.lua b/lua/snacks/gh/types.lua
index 0b76592c..3c886914 100644
--- a/lua/snacks/gh/types.lua
+++ b/lua/snacks/gh/types.lua
@@ -133,6 +133,7 @@
 ---@field statusCheckRollup? snacks.gh.Check[]
 ---@field baseRefName? string
 ---@field headRefName? string
+---@field headRefOid? string
 ---@field isDraft? boolean
 ---@field reviews? snacks.gh.Review[]
 ---@field reviewThreads? snacks.gh.review.Thread[]
diff --git a/lua/snacks/picker/config/defaults.lua b/lua/snacks/picker/config/defaults.lua
index cea49600..77f9e3c9 100644
--- a/lua/snacks/picker/config/defaults.lua
+++ b/lua/snacks/picker/config/defaults.lua
@@ -2,7 +2,7 @@ local M = {}
 
 ---@alias snacks.picker.format.resolve fun(max_width:number):snacks.picker.Highlight[]
 ---@alias snacks.picker.Extmark vim.api.keyset.set_extmark|{col:number, row?:number, field?:string}
----@alias snacks.picker.Meta {line?:number, [string]:any}
+---@alias snacks.picker.Meta {[string]:any}
 ---@alias snacks.picker.Text {[1]:string, [2]:(string|string[])?, virtual?:boolean, field?:string, resolve?:snacks.picker.format.resolve, inline?:boolean}
 ---@alias snacks.picker.Highlight snacks.picker.Text|snacks.picker.Extmark|{meta?:snacks.picker.Meta}
 ---@alias snacks.picker.format fun(item:snacks.picker.Item, picker:snacks.Picker):snacks.picker.Highlight[]
diff --git a/lua/snacks/picker/config/sources.lua b/lua/snacks/picker/config/sources.lua
index d3d4ad49..92d1dedf 100644
--- a/lua/snacks/picker/config/sources.lua
+++ b/lua/snacks/picker/config/sources.lua
@@ -282,11 +282,12 @@ M.gh_diff = {
   group = true,
   finder = "gh_diff",
   format = "git_status",
-  preview = "diff",
+  preview = "gh_preview_diff",
   win = {
     preview = {
       keys = {
         ["a"] = { "gh_comment", mode = { "n", "x" } },
+        ["<cr>"] = { "gh_actions", mode = { "n", "x" } },
       },
     },
   },
diff --git a/lua/snacks/picker/core/actions.lua b/lua/snacks/picker/core/actions.lua
index f2631de8..d6848c7f 100644
--- a/lua/snacks/picker/core/actions.lua
+++ b/lua/snacks/picker/core/actions.lua
@@ -32,7 +32,6 @@ end
 ---@param action snacks.picker.Action.spec
 ---@param ref snacks.Picker.ref
 ---@param name? string
----@return snacks.win.Action?
 function M.wrap(action, ref, name)
   local picker = ref()
   if not picker then
@@ -40,6 +39,7 @@ function M.wrap(action, ref, name)
   end
   action = M.resolve(action, picker, name)
   action.name = name
+  ---@type snacks.win.Action
   return {
     name = name,
     action = function()
diff --git a/lua/snacks/picker/preview.lua b/lua/snacks/picker/preview.lua
index 822343b1..74cecb94 100644
--- a/lua/snacks/picker/preview.lua
+++ b/lua/snacks/picker/preview.lua
@@ -188,7 +188,6 @@ local function fancy_diff(diff, ft, ctx)
   local buf = ctx.preview:scratch()
   ctx.preview.win:map()
   require("snacks.picker.util.diff").render(buf, ns, diff, {
-    ft = ft,
     annotations = ctx.item.annotations or ctx.picker.opts.annotations,
   })
   Snacks.util.wo(ctx.win, ctx.picker.opts.previewers.diff.wo or {})
diff --git a/lua/snacks/picker/source/gh.lua b/lua/snacks/picker/source/gh.lua
index 7737bdbd..fad4f64c 100644
--- a/lua/snacks/picker/source/gh.lua
+++ b/lua/snacks/picker/source/gh.lua
@@ -15,10 +15,15 @@ M.actions = setmetatable({}, {
     local action = {
       desc = Actions.actions[k].desc,
       action = function(picker, item, action)
+        local items = picker:selected({ fallback = true })
+        if item.gh_item then
+          item = item.gh_item
+          items = { item }
+        end
         ---@diagnostic disable-next-line: param-type-mismatch
         return Actions.actions[k].action(item, {
           picker = picker,
-          items = picker:selected({ fallback = true }),
+          items = items,
           action = action,
         })
       end,
@@ -307,6 +312,19 @@ function M.format(item, picker)
   return ret
 end
 
+---@param ctx snacks.picker.preview.ctx
+function M.preview_diff(ctx)
+  Snacks.picker.preview.diff(ctx)
+  local item = ctx.item.gh_item ---@type snacks.picker.gh.Item?
+  if item then
+    vim.b[ctx.buf].snacks_gh = {
+      repo = item.repo,
+      type = item.type,
+      number = item.number,
+    }
+  end
+end
+
 ---@param ctx snacks.picker.preview.ctx
 function M.preview(ctx)
   local config = require("snacks.gh").config()
diff --git a/lua/snacks/picker/util/diff.lua b/lua/snacks/picker/util/diff.lua
index 6168a519..742c2757 100644
--- a/lua/snacks/picker/util/diff.lua
+++ b/lua/snacks/picker/util/diff.lua
@@ -3,7 +3,6 @@ local M = {}
 ---@class snacks.diff.Config
 ---@field max_hunk_lines? number only show last N lines of each hunk (used by GitHub PRs)
 ---@field hunk_header? boolean whether to show hunk header (default: true)
----@field ft? "diff" | "git"
 ---@field annotations? snacks.diff.Annotation[]
 
 ---@class snacks.diff.Annotation
@@ -14,6 +13,11 @@ local M = {}
 ---@field line number
 ---@field text snacks.picker.Highlight[][]
 
+---@class snacks.diff.Meta
+---@field side "left" | "right"
+---@field file string
+---@field line number
+
 ---@class snacks.diff.ctx
 ---@field diff snacks.picker.Diff
 ---@field opts snacks.diff.Config
diff --git a/lua/snacks/picker/util/highlight.lua b/lua/snacks/picker/util/highlight.lua
index 6c2acaef..bb9e5064 100644
--- a/lua/snacks/picker/util/highlight.lua
+++ b/lua/snacks/picker/util/highlight.lua
@@ -2,7 +2,7 @@
 local M = {}
 
 ---@class (private) vim.var_accessor
----@field snacks_meta? snacks.picker.Meta[]
+---@field snacks_meta? table<number,snacks.picker.Meta>
 
 M.langs = {} ---@type table<string, boolean>
 M._scratch = {} ---@type table<string, number>
@@ -471,6 +471,19 @@ function M.fix_offset(hl, offset, start_idx)
   return hl
 end
 
+--- tables with number as keys are stored in vim.b as an array,
+--- so we need to filter out vim.NIL
+---@param buf number
+function M.meta(buf)
+  local ret = {} ---@type table<number, snacks.picker.Meta>
+  for k, v in pairs(vim.b[buf].snacks_meta or {}) do
+    if v ~= vim.NIL then
+      ret[k] = v
+    end
+  end
+  return not vim.tbl_isempty(ret) and ret or nil
+end
+
 ---@param dst snacks.picker.Highlight[]
 ---@param src snacks.picker.Highlight[]
 function M.extend(dst, src)
@@ -492,7 +505,7 @@ function M.render(buf, ns, lines, opts)
     vim.api.nvim_buf_clear_namespace(buf, ns, 0, -1)
   end
 
-  local meta = {} ---@type snacks.picker.Meta[]
+  local meta = {} ---@type table<number, snacks.picker.Meta>
 
   local changed = #lines ~= #old_lines
   local offset = opts.append and vim.api.nvim_buf_line_count(buf) or 0
@@ -504,8 +517,7 @@ function M.render(buf, ns, lines, opts)
       changed = true
     end
     if line_meta then
-      line_meta.line = offset + l
-      meta[#meta + 1] = line_meta
+      meta[offset + l] = line_meta
     end
     for _, extmark in ipairs(extmarks) do
       local e = vim.deepcopy(extmark)
diff --git a/lua/snacks/picker/util/init.lua b/lua/snacks/picker/util/init.lua
index 050ef240..c80c5f24 100644
--- a/lua/snacks/picker/util/init.lua
+++ b/lua/snacks/picker/util/init.lua
@@ -196,6 +196,7 @@ function M.visual()
   local text = table.concat(lines, "\n")
   ---@class snacks.picker.Visual
   local ret = {
+    buf = vim.api.nvim_get_current_buf(),
     pos = pos,
     end_pos = end_pos,
     text = text,