Running Xojo 2017 R3 on Mac and Windows. This happens only on Mac when debugging. Same code on both machines. I choose a file and the GetFileOpenFolderItem does not close. When I get to a break point following this I can't work with the debugger window. I have to move it over to a new OS window. This is new as I've been working with this app for over a year. Maybe a High Sierra issue?