Ecdesign will show a missing object menu, if trying to open a layout with objects which you currently do not have installed.
To solve this, click on the "Update Now" button to run an assortment update check.
Ecdesign will check for new updates. In the Object menu a green icon will appear next to the vendor name. Click on the green icon to download the new objects.
Here is a view of the Object menu showing the green update button. Click on it to update.