I get the same thing. Instead of trashing a plist and a cache, I tried simply resetting my preferences. They seem to stick for awhile and then revert. I can't explain it.
All I do is reset my prefs; it's easier than and just as effective as trashing stuff.
The new Great Equalizer is the SEND button.
In Memory of Harv: Those who can make you believe absurdities can make you commit atrocities. ~Voltaire