search function and editormonkey

i have quite weird problem with search function in wordpress. if i am using built-in rich editor everything is searched good (including czech special characters), but when i am using editomonkey, it converts czech characters into something like this á instead of “á” and so on. and that is the problem. the built-in and any other plugin search function aren’t working with this. is any possibility to solve this?

page with problem: https://scsf.cz