How to disable annoying popups

Hello,

I think it is time I call for help here: I am getting more and more annoyed by these blue popups that appear above non-resolvable variable names and make nonsensical suggestions like ""varname" from <some totally remote and unrelated header>?". Not only do they seriously hamper my work, but also from time to time I seem to unintentionally accept the suggestion, which leads to these strange headers being #included in my file, with ensuing compile errors. I searched the settings dialog, but nothing seemed obvious. I would REALLY appreciate if I could get rid of this!

thanks,
Christian