If you place a small control at the top of the screen, for example, an icon control, you can click it and the tooltip appears i.e. it's detectable in the edit mode when running play, but not in the full play mode itself.
Easilly reproducible ...
Add a icon control with properties: X=300, Y=0, Height=16, Width=32, Tootip="Hello", OnSelect=do-anything-your-want
When you hover on the control in edit mode run it works fine: You see the tooltip and the OnSelect does whatever you've made it do. But in Play mode the pointy finger doesn't appear, nor does the tootip, and the On Select doesn't work - except for a fine line along the bottom of the control which you can point at if you're accurate and patient.
It appears like there's a border along the top of the screen that Player doesn't process, but edit mode run does.
Or maybe I'm missing something?
You can work around this by making the icon bigger or moving it down the screen, so more of it pokes below the Player's "top border black hole". But in my app the whole point is that the top nav of the app has an expand and collapse thing going on to create screen estate for the users. I want the down arrow "Click to expand" icon to be tucked right up at the top of the screen in as small as possible a space to provide as much screen estate as possible for the users.
