If you see this issue in the default Gmail theme also, with Labs disabled, and after having cleared your browser's cookies and cache, can you let me know the Gmail version?

Thanks!

Yes, the problem was solved with changing back to the original Theme.

Are you working on a fix to make RTM functional with Themes?

Thanks

I've added it to our list to investigate; thanks for letting us know!

Also, for what it's worth, these are the themes that don't appear to work currently:
* Not visible: New Blue, Night Shade, Shiny, Beach, Mountains, Pebbles, Summer Ocean, Phantasea, Ninja, Orcas Island, High Score, Turf
* Technically visible but with only minimal contrast: Sunset, High Contrast Black, Desk, Planets

All others work correctly.