I respectfully disagree. When the background for a keyword type is not specified (e.g. set to default) the current line highlight color should not be replaced with with the default color for a non highlighted line.
For example, there is no way to do this in EmEditor:
It looks like this:
Note that the cursor is on line 5 in both cases. I don’t have white set explicitly for the background color of strings for example. If I am missing something, please explain.