Prior to this PR, marker layers and symbol layers had to have at least one marker / symbol. This doesn't play well with dynamic applications, where it's reasonable to sometimes have no markers or symbols. See e.g. the example application where the app should still work if both checkboxes are de-selected.
This PR also updates the tests to test against the marker and symbol layers directly.
Prior to this PR, marker layers and symbol layers had to have at least one marker / symbol. This doesn't play well with dynamic applications, where it's reasonable to sometimes have no markers or symbols. See e.g. the example application where the app should still work if both checkboxes are de-selected.
This PR also updates the tests to test against the marker and symbol layers directly.