When I first power on the TV, the Roku seems to override the input to select the HDMI input on the TV that it's connected to. Upon further investigation, this seems to be the option in the Roku called "1-touch play". This is fine if all that was used was the Roku. But when I would switch inputs (e.g. to watch cable TV or a DVD) via the Harmony remote, the default-to-Roku behavior of the TV when it's powered on was confusing the remote. The TV is unfortunately one that requires pressing a "source" button, and then the appropriate number of "up" or "down" buttons to select the input you want. There's no "select HDMI2" button that can be programmed into the remote.
In the process of figuring out a scheme that would be Harmony-friendly, I disabled the "1-touch play" option in the Roku. (roku settings> system> control other devices (CEC)> uncheck 1-touch play box). This made the TV no longer default to the Roku when it's powered on. But sadly made the Harmony input-selection problem even worse than before.
Wanting to get back to where I started, I re-checked the 1-touch play box in the Roku settings. However, even with this change (and restarting the Roku *and* the TV and just about anything else I could think of), the TV no longer automatically selects the Roku input when it's powered on!
Has anybody else noticed this behavior? That is, once 1-touch play is disabled in the Roku settings, re-enabling it doesn't actually turn it back on?