WPF Slowness and Unmanaged Debugging

Beat my head against a wall for a while today trying to figure out why our WPF application was running so slowly. Debugging, profiling, tracing, spelunking through file histories, all to no avail.

Turns out it was enabling unmanaged debugging in the project properties to use SOS.dll to trace some memory leak issues. This creates a HUGE performance overhead in WPF applications. Beware!