Weird but it is becoming problem for me!
I have added an html checkmark with this code ✔ to my linkbutton text but when I am trying to check this
if(headerLinkButton.Text == "✔")
it returns me false!
and when I check its text putting breakpoint, it shows the same checkmark that it shows on browser!

Strange How can I simulate a checkmark in my code?
Try this instead :
Or Alternately
Hope this will help !!