question

I recently opened my app on a Fire Stick 4K for the first time and I immediately saw 2 significant differences. The 4K renders the action bar while previous Fire TVs did not. Second, the option menu when opened from the ActionBar has the right appearance (black text, white background), but when opened with the Menu button on the remote (3 lines) it has a black text on nearly black background though on the pre-4K devices it is black text on the white background. Is there some list of differences, or are there known solutions? I have searched Google and this forum but have not found other mentions of this.