Crash and weird behavior with unknown characters (ü and maybe others)

[GarompaEstomper]

Recently I came across a problem with some maps that contained entities with the word "targetname" "tür".
It displayed the "ü" as a "?" and when selecting the name to change it the newbspguy did weird things with the character/letter input, deleting the last 2 chars, disappearing the entire input, etc, weird stuff.

I was not going to report this, but then today, it crashed because of that. I had to change all those characters to a normal character in a text editor then import the ent file again. I believe this is easily reproducible, just create a bunch of entities that trigger each other and have a ü and try to edit them later.

I believe there might be other characters that may cause this.

[Qwertyus3D]

Cürsed