It’s a known issue, and Roon Labs are aware of it. Better accessibility has been flagged as a Feature Request a number of times, e.g.:
Unfortunately, as @danny pointed out in that thread, Roon’s UI doesn’t use the built-in primitives of the OS (Windows or MacOS) for display, and it would take a complete redesign of the UI to do so.
Whether a future redesign of the UI will take this issue into account, only Roon Labs can say - and they have a policy of never (well, hardly ever) commenting on Feature Requests…