FLAW in Time Machine with MAIL Full Screen with El Capitan

I have upgraded my 27" iMac (Late 2013 purchased last December).

I noticed yesterday (10/7/15) that I could not enter Time Machine when in MAIL with FULL screen. Time Machine was huge, the "RESTORE" and "CANCEL" buttons were covered. The dock was visible every time I moved the cursor to the bottom; The Mail app froze after using ESCAPE or Command Option Escape preventing me to go into Safari.

Using regular screen and not full going into Time Machine with Mail worked as it should (with the exception of having to re-size the Time machine window and dragging it so that the "restore" and "cancel" buttons could be seen. Going intoTime Machine in FULL screen with other apps (such as Safari, and Music) worked normally.

I called AppleCare and I was escalated to a senior advisor who initially recommended re-installing the operating system (no thanks!). Then, she tried this with her Mac and the SAME exact issue! I was asked to send my files that she captured for review by their engineers. So apparently I have uncovered a flaw in El Captian since Mac.

Try ENTERING Time Machine in MAIL with full screen. I'm glad I didn't do a re-install of the OS X.