I have never figured out how to save and apply my custom them to a menu page without changing existing buttons.

I created a MENU page with the layout I want. The buttons all have text and a square video thumnail. When I create the next menu, I enter in the new texts but when I apply my theme, it changes all of the text to the menu that I created the theme from. Is there any way to keep it from changing the text when applying a theme?