Category Archives: Windows 10

Strange white on black numbers during debug in Visual Studio 2015

When running a Universal Windows application in debug mode within Visual Studio 2015 I noticed some “strange” white numbers on a black background adorning my application window (and in the case of a desktop application displayed on the top right of the screen).

It seems these are enabled via the App.xaml.cs file, within the OnLaunched method (the code in some cases may appear in the App() constructor according to the documentation) there’s the following code

#if DEBUG
   if(System.Diagnostics.Debugger.IsAttached)
   {
      this.DebugSettings.EnableFrameRateCounter = true;
   }
#endif

See also DebugSettings.EnableFrameRateCounter property.

As stated within the above link, this causes an overlay of two sets of numbers. Those in the upper left of the screen/Window relate to the application being debugged those in the upper right apply to the overall system.

Basically the left number is the app’s UI frame rate in frames per second and the right number is the CPU usage of the app’s UI thread per frame in milliseconds.