SlickRun seems to have issue with IME.
IME (Input Method Editor, see https://en.wikipedia.org/wiki/Input_method
) is commonly used by Chinese/Japanese/Korean users. IME has 2 modes: English (system language) mode / IME language mode. When the user is in the IME (non-English) mode, anything typed in IME window gets doubled in SlickRun window (for example, when user types 'abc in IME', SlickRun gets 'abcabc').
Since I have all magic words in ASCII/English letters, I propose that SlickRun offers an option to totally disable IME, i.e., if "totally disable IME" is enabled, when the user switches to SlickRun window, the IME would be disabled (and appear as in English mode), by simply calling ImmDisableIME(-1).