Ultra-light keyboard layout switch

From a lot of wisdom a lot of grief, and multiplying knowledge multiplies sadness: the deeper one delves into the specifics of the IT world, especially the part about information security, the stronger is paranoia. And this does not mean that you are not being watched. In the next attack of concern for the safety of the pressed buttons, I deleted the Punto Switcher. However, without switching the layout after the already typed word to which I was so used, it became very depressing. I did not find any sane alternatives, so I had to write a small wrapper over a pair of win api functions.

Perhaps the result of a few days of poking a twig in user32.dll will be needed by several more people, either as a program itself, or as an example of sending messages to windows from .Net, so here is an analogue of punto switcher , without whistles, fakes and Yandex bars.

Unfortunately, in Skype does not work. I would be grateful if someone experienced would point me to errors in the code.

UPD .: Important, judging by the comments, clarification: correction of the last typed word occurs only by pressing Pause / Break. Autoswitches are evil.