Splitting from T258090#6328515 :
Steps:
- Go to https://it.wikivoyage.org/wiki/Firenze#Basilica_di_Santa_Maria_Novella
- Click blue box 1 to open https://it.wikivoyage.org/wiki/Firenze?debug=true#/maplink/4
- Press Esc on keyboard
Result:
dialog.map is null in Firefox 82; TypeError: Cannot read property 'parentMap' of null in Chromium 86