Try this. In PS Preferences, go to "Interface". Under "Options", uncheck "Show Tool Tips". I think that should take care of this particular annoyance. If necessary, you can of course turn that Pref back on and then off again when you no longer need it. I was having an issue with Camera Raw CS6 on High Sierra. The tool tips were sticking and the only way I could get rid of them was to shut down PS. The first reply to my post on the Adobe forum was the procedure I've mentioned above, and it worked perfectly. I do keep that Pref checked until I know I'll be using Camera Raw, and then I uncheck it for that purpose only. At first this seemed too simple to solve my problem, but of course it did. It seems that sometimes the most obvious approach is the answer. I hope this helps.
In photoshop cc 2018 there is a new kind of tooltip called Rich Tooltips and that's what your seeing.
You can turn that off in the Photoshop CC (mac) or Edit (windows) Preferences>Tools>Use Rich Tooltips
Let's hope Adobe make these new features OFF default in the future and serve a text telling us about new stuff for instance on first launch after update instead of forcing them ON as default.