Spark 2.6.0 RC1 idle detection issue on WinXP

Spark 2.6.0 RC1 rocks. My only (minor) gripe with it is that keyboard activity alone does not keep Spark from thinking the computer is idle. Mouse activity is required as well on my machine. Is there a setting I’m missing, or am I doing something wrong? Or is this an issue with 2.6.0 RC1 which I did not have with the 2.5.8 client? Thanks.