Please help.

I created a new dropdown list in dropdown editor. I added 2 values in dropdown editor and then I opened custom/include/language en_us.php and copy pasted 100 more values in correct format.

Now I see all 102 values in Dropdown editor, but some values with letters from other language like "ä, õ, ü" are displayed with missing characters. Like Hrt instead of Hürt

I see it is correct in custom/include/language en_us.php - Hürt

How can I fix this, for Dropdown editor to display Hürt, not Hrt ?