Cant assign sidecar configuration in UI

Running latest graylog 6.3.0 and decided to try out sidecars for filebeat configurations.

Adding the sidecar is no problem, however I created an additional configuration for filebeat logs but am unable to assign the configuration to the sidecar as the “confirm” pop-up window appears to open up behind the configuration window..

Sidecars → Administration → Select sidecar filebeat where i want to add → Assign Configurations (top right) → select additional config to add → Save … (confirmation summary pop-up opens behind and cant be clicked).

Pressing cancel then shows the confirmation window, but this then no longer works.