setUsingNativeTitleBar true vs. false CPU usage


I’ve noticed that setting setUsingNativeTitleBar(true) causes a blank Juce application with no ContentComponent to use significantly more CPU when dragging it around the screen. I’ve double checked this behavior on 3 different WindowsXP machines:

MacBook Pro WindowsXP 2.3GHz Core2Duo (10% - 18% CPU Usage)
Generic WindowsXP 2.6GHz Core2Quad (10% - 12% CPU Usage)
DellTower WindowsXP 2.4Ghz Core2Duo (10% - 19% CPU Usage)

When setting setUsingNativeTitleBar(false) the CPU is at 0% - 1%.

The size of my app is 800 x 600.

This can also be seen in the jucedemo.exe (Just flip between the “Use native window title bar” menu item) and look at the task manager.

Has anyone else experienced this?

I just want to know why the native bar would cause more CPU usage. The juce title bar looks a bit more complex to draw. Or is it the way the native frame handles the juce stuff inside of itself vs. juce title bar/frame?

Just Curious.

It could be that when you’re dragging a native one, it repaints more often?