Problem with .ui form

[Fenix Voltres]

Hello,
I'm making program in Qt Creator and today I have encountered a problem - when I change something in one of my .ui form files included in my project and then I build it - nothing changes... (Graphically my MainWindow looks exactly like previous version, despite the fact that I changed something in adequate file... Already tried restarting Qt, rebooting my computer, even built Qt again, but the problem still exists.
Interesting thing is when I hit ctrl+alt+r (preview) I see what I should... What's more: after removing my .ui file it still builds project! I tried to delete all Makefile's and whole debug folder, of course in vain.
Do you know, what could be the reason for this?

Thanks in advance,
Fenix Voltres

[EDIT]

OK, found it - Creator added "\" sign in my .pro file before "FORMS".