YES! This is another feature that is surprisingly yet to be functional.
Thanks for your awesome feedback! Defining exact hex color value, entering exact thickness/opacity/text size value is now available in Xodo beta! See http://feedback.xodo.com/knowledgebase/articles/1119511-change-style-of-an-annotation-color-thickness-o.
To enter exact color HEX value, see: http://feedback.xodo.com/knowledgebase/articles/1849546-annotation-color-picker.
To define and select style presets, see: http://feedback.xodo.com/knowledgebase/articles/1851553-setting-an-annotation-style-preset
You can become our beta tester as described here: http://feedback.xodo.com/knowledgebase/articles/829551-becoming-a-beta-tester.
Just FYI, “more”/“plus” button for adding customized tools to toolbar is under review! Hopefully we can implement it in the future!
YES YES YES THIS and s- pen button functionality and customizable toolbar!!! = Perfect program
S-pen button as eraser... or even better, s- pen button is customizable to user defined function (eraser, selection, highlighter, etc.) . Please!