Events flash when opening

## What Happened

https://user-images.githubusercontent.com/39268094/128988696-ffe6e098-6f5e-4bfc-a502-270ae19fe890.mp4

## Expected Behavior

Events should not flash

## Steps to Reproduce

1. Add some events
2. Open wingpanel-indicator-datetime

### Logs

## Platform Information

---
Want to back this issue? **[Post a bounty on it!](https://www.bountysource.com/issues/100729468-events-flash-when-opening?utm_campaign=plugin&utm_content=tracker%2F57456330&utm_medium=issues&utm_source=github)** We accept bounties via [Bountysource](https://www.bountysource.com/?utm_campaign=plugin&utm_content=tracker%2F57456330&utm_medium=issues&utm_source=github).