@mischag ok, so I think you need to reduce the config the the two modules
Calendar and ext3timeline

Simplest is to add
disabled: true,
To each other module after its position line

Then once you solve this, change true to false

@mischag ALL config for ALL modules goes in config.js.
all the stuff in a module config BEFORE the config:{} section is info for the MagicMirror runtime. everything inside the config:{} section belongs to the module

so in the MMM-CalendarExt3 module config section

maybe you want a transformer as you want to change it

{ module:'MMM-CalendarExt3', position: xxx , config:{ mode:'month', eventTransformer: (event) => { if(event.title.includes('Mary') event.color='red' // always return the event return event; }, } }