Description of problem:

Got white screen when connectors of event source dragged over the revision of knative service

Prerequisites (if any, like setup, operators/versions):

The serverless operator should be installed

Steps to Reproduce

1. Create two knative service
2. Create an event source(api server source, ping source)
3. Move the connector over the revision of service

Actual results:

Expected results:

Should be a better way of handling it

Reproducibility (Always/Intermittent/Only Once):

Intermittent

Build Details:

4.7.0-0.nightly-2021-01-10-070949

Additional info: