Control mode on Screen Sharing doesn't work - Solved

Running Mountain Lion on iMac and Macbook Pro, "Back to my Mac" activated on both computers, using an Airport Extreme, everything set up correctly near as I can tell based upon online instructions. Am able to view the iMac remotely but the "Switch to Control Mode" selection is dimmed and cannot do mouse clicks or keyboard entries of course. Have consulted the Settings on the iMac, "Screen Sharing" button on Sharing page is unclicked, selecting it declares "Screen Sharing is currently being controlled by Remote Management".

Found no answers online here so thought I'd share the cause: Somewhere along the line the "Remote Management" button was selected during a previous setup for RDP. Going ahead and activating the more convenient "Screen Sharing" method through iCloud did not uncheck this box. Uncheck that Remote Management box and select "Screen Sharing" instead and you are good to go.