fix(menu): allow relative win settings other than win

Ensures `win` key is nil if `win_configs.relative` ~= `"win"`,
and sets the fzf window location relative to the main window instead
of calculating the `relative="editor"` width.

lua/dropbar/menu.lua

@@ -490,6 +490,10 @@ function dropbar_menu_t:open_win()
   end
   self.is_opened = true
 
+  if self._win_configs.relative ~= 'win' then
+    self._win_configs.win = nil
+  end
+
   self.win = vim.api.nvim_open_win(self.buf, true, self._win_configs)
   vim.wo[self.win].scrolloff = 0
   vim.wo[self.win].sidescrolloff = 0
@@ -888,15 +892,26 @@ function dropbar_menu_t:fuzzy_find_open(opts)
     col_offset = 1
   end
 
-  local win = vim.api.nvim_open_win(
-    buf,
-    false,
+  local win_config =
     vim.tbl_extend('force', self._win_configs, opts.win_configs or {}, {
-      row = self._win_configs.row + self._win_configs.height,
-      col = self._win_configs.col - col_offset,
+      relative = 'win',
+      win = self.win,
+      row = self._win_configs.height,
+      col = col_offset,
       height = 1,
     })
-  )
+  -- don't show title in the fzf window
+  win_config.title = nil
+  win_config.title_pos = nil
+
+  -- hide the top border if possible
+  if type(win_config.border) == 'table' then
+    win_config.border[1] = ''
+    win_config.border[2] = ''
+    win_config.border[3] = ''
+  end
+
+  local win = vim.api.nvim_open_win(buf, false, win_config)
   vim.wo[win].stc = opts.prompt
   _G.dropbar.menus[win] = self
   self.fzf_state = utils.fzf.fzf_state_t:new(self, win, opts)