node.editor.screen_top1, node.editor.top = schema1_of_y(node.editor, scale(Viewport.y-node.y))  -- scale y because editor's font is scaled
			node.editor.top = node.editor.top + Menu_bar_height
			print('modified screen_top to', node.editor.screen_top1.line, 'at', node.editor.top, 'vpx')

		else
			-- adjust editor to start rendering near top of viewport
--? 			print(Viewport.y)
			node.editor.top = Viewport.y%node.editor.line_height
			if node.editor.top > 0 then node.editor.top = node.editor.top - node.editor.line_height end
--? 			print('top', node.editor.top)

			node.editor.screen_top1, node.editor.top = schema1_of_y(node.editor, scale(Viewport.y-node.y))
--? 			print('modified screen_top to', node.editor.screen_top1.line, 'at', node.editor.top, 'vpx')

		node.editor.top = node.editor.top + Menu_bar_height

--? 		print('edit', old_top.line, '=>', Cursor_node.editor.screen_top1.line)
--? 			print('modifying Viewport', Viewport.y, 'based on', Cursor_node.y, Cursor_node.editor.screen_top1.line, Cursor_node.editor.line_height)

--? 			print('edit', old_top.line, '=>', Cursor_node.editor.screen_top1.line)

--? 				print('modifying Viewport', Viewport.y, 'based on', Cursor_node.y, Cursor_node.editor.screen_top1.line, Cursor_node.editor.line_height)

--? 				print('modified Viewport', Viewport.y)

--? 			print('modified Viewport', Viewport.y)