Tabindex ruined by IE 11

We made serious effort to build a complex form with a sequence of tabindex. This worked in almost every browser seamlessly, but with the latest release of IE 11 the sequence is really messed up. When our form is opened in IE we can't see what the first tabindex is and after hitting TAB several times the focus appears in the form, but not in the sequence as configured. Anyone who could share their experiences and best practices with tabindex in IE?
1 answers

What debugging have you done? Have you gone in with developer tools (F12) to ensure the tabindex attribute is being properly set to each of your html elements? Also, is the issue on a specific form, or on all of them?