Anne Gropler

`time` param of CallbackProperty.Callback should be optional

1

### Feature According to the [current signature](https://cesium.com/learn/cesiumjs/ref-doc/CallbackProperty.html#.Callback), the callback has 2 params: 1. `time`, of type `JulianDate` 2. `result`, an optional object This implies that every CallbackProperty is time dependent....

### What happened? I have an app with some labels that have a background. The labels can be hidden and shown again, and they can be updated (e.g., font size...

### Validations - [X] Follow our [Code of Conduct](https://github.com/eslint-stylistic/eslint-stylistic/blob/main/CODE_OF_CONDUCT.md) - [X] Read the [Contributing Guide](https://eslint.style/contribute/guide). - [X] Check that there isn't already an issue that reports the same bug to...

ImageOverlay always has a z-index of 1 and thus is not drawn over a Rectangle

3

### Checklist - [X] I've looked at the [documentation](https://leafletjs.com/reference.html) to make sure the behavior isn't documented and expected. - [X] I'm sure this is an issue with Leaflet, not with...