ARCHICAD 19 onwards now allow you to hide a label with its associated element. By ticking the option in Label Selection Settings, the Label will automatically be hidden when you hide the layer where the element has been placed.
Open the Keynotes Palette from Cadimage > Keynotes > Keynotes Palette. To attach notes to elements Select the elements then: 1. Make sure you have it set to Element labels. 2. Make sure the key note palette is on Full Notes 3. Double click on the notes to add them to the selected elements To