How old is this, meaning, has it been like this for several hours? Try swapping the wallpaper and floor swatches; and seeing if it takes care of it. Last resort, clear cache and restart the browser after. The reason being is we think we fixed this bug several hours ago. So.. try the above suggestions to start.
Ummm...this has happened to me, as well. I tried doing as kevbob suggested and clearing cache and restarting browser (I'm on latest version of Firefox), but it's still there...and I cannot apply a swatch to it...it will not highlight blue to allow me to do so.
Just went there, the Brown Bog wall covering is all the way on the right side. So, looks fine to me. Jump over to Safari for a moment and see if you notice a difference. If so, try another cache clear on Firefox.
I've got the "mirroring" effect going on on my third floor. I don't mind it, but it won't let me add any swatch and I get that "UncaughtErrorEvent type="uncaughtError" bubbles=true cancelable=true eventPhase=2]TypeError: Error #1009" message.
After that message, I must get out of the game completely. Even using the debugger version, clearing the cache, and using different browsers, it still gimps up.