1366x768 Resolution Missing on Thunderbolt Display

I've updated my MBP to Mavericks but I haven't needed to change the screen resolutions often. This changed when I installed Parallels, which made use of the system-available resolution settings to create its own set of virtual resolutions.

This caused a lot of issues because I've noticed that there was no 1366x768 option in Parallels! Now to achieve this specific resolution I had to stretch the window to the size of 1366x768.

What concerns me is that this ubiquitous resolution is not available on the Mac side of things. Instead, a nonstandard 1344x752 resolution is there which doesn't cut it at all for me. Even more baffling is that 1366x768 was available in the past but has been removed!

I tried to use SwitchResX to add the resolution to the list, but this ended up in the Thunderbolt Display blacking out in clamshell mode. When out of clamshell mode the display ran concurrently with the laptop display, but the 1366x768 resolution did not work at all.

Is anyone else experiencing this and does anyone know how to remedy it?