Hrmm, I cant get the setting to stick in there in qt.
Under debug build I click > Add > String > Edit the <UNSET> fields WANT_DEBUG and 1
Click file > save all
Close qt creator, reopen and my setting is no applied. If i try and build without restarting, I get the not a debug build error.
Can you check if this setting is being written to a file somewhere? If i can change that file, I may be able to work around the issue.