add padding first column

lua/nvim-tree/renderer/builder.lua

@@ -101,7 +101,7 @@ end
 ---@param end_ number|nil
 function Builder:insert_highlight(groups, start, end_)
   for _, higroup in ipairs(groups) do
-    table.insert(self.hl_range_args, { higroup = higroup, start = { self.index, start, }, finish = { self.index, end_ or -1, } })
+    table.insert(self.hl_range_args, { higroup = higroup, start = { self.index, start }, finish = { self.index, end_ or -1 } })
   end
 end
 
@@ -381,8 +381,28 @@ end
 function Builder:build_header()
   if view.is_root_folder_visible(self.explorer.absolute_path) then
     local root_name = self:format_root_name(self.explorer.opts.renderer.root_folder_label)
-    table.insert(self.lines, root_name)
-    self:insert_highlight({ "NvimTreeRootFolder" }, 0, string.len(root_name))
+
+    -- Pad to window width so the highlight spans the whole row.
+    local win = view.get_winnr()
+    local width = 0
+    if win and vim.api.nvim_win_is_valid(win) then
+      width = vim.api.nvim_win_get_width(win)
+    end
+
+    -- Use display width for proper padding with Nerd Font / wide glyphs.
+    local name_display_w = vim.fn.strdisplaywidth(root_name)
+    local pad = 0
+    if width and width > name_display_w then
+      pad = width - name_display_w
+    end
+
+    local padded_root = pad > 0 and (root_name .. string.rep(" ", pad)) or root_name
+
+    table.insert(self.lines, padded_root)
+    -- Highlight the entire padded string (covers the full visible row)
+    self:insert_highlight({ "NvimTreeRootFolder" }, 0, string.len(padded_root))
+
+    -- Keep original indexing behavior
     self.index = 1
   end
 
@@ -395,7 +415,6 @@ function Builder:build_header()
     self.index = self.index + 1
   end
 end
-
 ---Sanitize lines for rendering.
 ---Replace newlines with literal \n
 ---@private
@@ -449,7 +468,8 @@ function Builder:setup_hidden_display_function(opts)
       local ok, result = pcall(hidden_display, hidden_stats)
       if not ok then
         notify.warn(
-          "Problem occurred in the function ``opts.renderer.hidden_display`` see nvim-tree.renderer.hidden_display on :h nvim-tree")
+          "Problem occurred in the function ``opts.renderer.hidden_display`` see nvim-tree.renderer.hidden_display on :h nvim-tree"
+        )
         return nil
       end
       return result