I found a bug with input in the expression editor on systems that have more than 1 language. This happens to me both natively on my PC and on my Mac in Parallels Desktop. It also happened before version 294 but I always restarted the engine to bypass this problem as I hadn't found the time to report this, though it becomes very inconvenient and would much appreciate Clickteam if you could try to reproduce this on your end and perhaps fix this in a future update.
Some more info:
On my system I have English and Hebrew input languages. It happens that even though the input is set to ENG, when I begin to type in the expression editor it types the first letter in English correctly, but then immediately changes the input langauge to Hebrew. Same goes when I change the input to HEB and start typing in the expression editor - the first letter types in Hebrew and the rest in English.
If I go into another program like Notepad and try to reproduce the issue it doesn't happen - when I'm in ENG it types in English and when I'm in HEB it types in Hebrew.
Sometimes when switching to other programs and getting back to the engine it fixes the issue, but only for a short amount of time. In the worse case I need to completely restart the computer.
I've captured a video describing the issue. You can see how the input language on the bottom right corner of the taskbar changes automatically when I type in the expression editor.