Right align header's custom menu, when in RTL mode
theme/nimble/style/menu.css
theme/nimble/style/menu_rtl.css
theme/nimble/config.php
theme/nimble/renderers.php
theme/nimble/pix/menu/*

Left align logininfo ,When in RTL mode
theme/nimble/style/core.css

Change $bodyclasses[] = 'has_custom_menu' to 'has-custom-menu' , on all themes (for consistency with other css class names)
theme/nimble/layout/frontpage.php
theme/nimble/layout/general.php