Problem with Dialog windows on a Mac

[pbacot]

I have moved to High Sierra with a MacBookPro and my dialog windows are misbehaving! Using SketchUp version 2016.

Instead of staying stacked when stuck together they display an array of bad behaviour. If you grab the top bar of of one to move the stack they drift apart in a vertical but random-seeming fashion. Opening a window by clicking on it no longer simply expands the stack. As you try to open and use them. Dialogs tend to stack directly on top of each other so you can't tell which are open or where they are.

It's very hard to describe, but essentially using the dialogs (such as scenes, shadows etc.) and positioning on the screen is just a random mess and no longer behave in a predictable manner. I think I am seeing problems of windows which I have "stuck" together only--but I can't be sure that is all.