The attached screenshots show a customized UI layout and a broken one that is Fiddler shows me on each start of the program.
The program window doesn't remember its on-screen position as well: it's always shown in the left half of my only display.
Telerik Fiddler Web Debugger (v126.96.36.199002)
64-bit AMD64, VM: 59,0mb, WS: 92,0mb
.NET 4.6.1 WinNT 6.1.7601 SP1