When attempting to write a string in Arabic in the expression window there will be times where as soon as you write 1 Arabic letter the typing language would automatically flip to English as seen in the attached video. I faced this problem on both windows 7 and windows 10 and it seems to happen randomly as sometimes it will allow me to type in Arabic just fine. It is not just Arabic it happens with Hebrew too as well.
So far the only way to fix it is to restart the pc everytime it happens. A work around is to type in a notepad then copy and paste into clickteam expression window but it gets annoying after a while