Does it go red for long periods at a time? Long enough that you can hover the mouse over it and tell me what pops up when it's red?

If you put:
debug=stake
in the clam.conf file in the same folder as your wallet.dat and restart, it will write stake-related stuff to debug.log in the same folder as it stakes.

You could "tail -f debug.log" in that folder and see whether anything looks different when it's red. Staking basically consists of hashing each of your staking outputs every 16 seconds and comparing the result with a target based on the network difficulty. If the output hashes lower than the target, you get to stake a block. "debug=stake" will cause these hashes that are being compared to be logged.