Handler of component is invalid -> ReferenceError: guidelib is not defined
I can't see any problems with the page other than this so it doesn't seem to be breaking anything but obviously it would be better for the editors not to see this warning display at the top of the edit mode window:
An error occurred, please check the browser console for more details.
I use 6.4 and I observed that issue ('guidelib' is not defined) occurs only in Edge in touch UI mode. I don't see any error in classic UI mode. Checked in Chrome, Firefox and IE. It looks fine in all of these 3 browsers in both the modes.