Comment 1 for bug 187772

Hmm, this one is a bit difficult to solve. At the moment the code iterates through all the persons, resources and groups to generate the list of possible overlays.

And it is impossible to cache these values, because the list is permission dependent.

One solution would be to redo the overlays completely, only leaving the list of "already overlayed" calendars in that view. And have people add the calendars by browsing to the calendar that they need and clicking "Overlay" button somethere in the UI.

So instead of combing through a list of 1000 persons in a listbox and no search you would go to the Persons container, find the person, go to his calendar and click "Overlay" or a huge "+" sign.

OTOH - who would want to overlay a calendar of another person ;) Maybe we should limit the view to groups?