I have confirmed the increase in CPU usage while dropdown menus are open.
I’m sure this is another .NET anomaly. Like the fluctuating memory issue, we are leaving a lot of tasks up to .NET to manage (as per proper procedure). While this ensure further compatibility and stability with Microsoft products, optimization becomes much more fuzzy.
I think we will look at optimization of the code once all features are in place. Then we will have a more clear idea what the total system impact is.