Tinymce Stacks Classes

I'm using TinyMCE 4 as my default editor. In the config I specified style formats. This works excuistly except for one thing: it stacks classes. My style format: style_formats: [

Solution 1:

Add style_formats_merge: true

style_formats_merge

This option allows you to set whether TinyMCE should append the styles in the style_formats setting to the default style formats or completely replace them.

Source