Hi Fabio,
Thanks for reaching out with your BoldGrid Post and Page Builder questions!
The Tiny MCE- (Advanced Editor) Tools were specifically meant to enhance the Gutenburg Block editor for WordPress so that would explain why some of the icons don’t transfer over to Post and page Builder. You can easily change the background of your text with Post and Page Builder by highlighting the text you’d like to change, click the “T” text icon, Customize Design and select the “Background Color” option to change your text background. We have a guide on Working with Fonts in Post and Page Builder that should help you understand our editor controls a bit better.
I hope this helps! Please let us know if there’s anything else that we can answer for you.