Reader not staying in fullscreen...

[Patrick5FAC]

I have a .pdf file set as a homepage in fullscreen view, with links to other files. Clicking on any of those links will open a .pdf file fullscreen in a new window. This is the homepage displaying in fullscreen as it should:

Clicking on one of the links will open a new .pdf file fullscreen in a new window. But when I close that new file, the homepage is no longer in fullscreen. Instead it appears like this:  

This is making me nuts. What settings to I have to set in order for the original homepage to remain in fullscreen?

Thank you inadvance for any and all help.