patch 8.2.0857: GTK cell height can be a pixel too much Commit: https://github.com/vim/vim/commit/5cd1cb9ff9d04979ff4cbc36ca8416d83364505d Author: Bram Moolenaar <Bram@vim.org> Date: Sun May 31 13:53:04 2020 +0200 patch 8.2.0857: GTK cell height can be a pixel too much Problem: GTK cell height can be a pixel too much. Solution: Subtract 3 instead of 1 when rounding. (closes https://github.com/vim/vim/issues/6168)