Thanks for your response .I also saw this issue ID 560518,but the customer didn't want to upgrade tableau server and tableau desktop ,due to they have used this product for a long time.I will talk to my customer again.Thank you very much.
I assume it fixes the problem - but don't have direct confirmation.
i wanted also to link to this thread and the sub-threads Color Code Change for legends
seems like its an issue for a few users - Dmitry seems to be on the case!
there are other advantages to be had by upgrading, v10 brought quite a few new features... but will rely on having a current maintenance license.
best of luck - hope you get it solved!