I closed a couple of document windows in my Dock to free up space to work in visual studio.
I assumed that those windows would not have been permanently deleted, but they appear
to be gone.  When I re-enter the advanced designer, I no longer see them.

Is there a way to recover or restore those document windows I had closed in the advanced
designer of the Dock?

Hello Greg,

Thank you for writing.

In the Advanced Layout Designer, there is a tree on the left side, which enlists all the ToolWindows and when you uncheck the check box of a certain ToolWindow it is not deleted, but it is rather hidden, thus, it can be shown later. However, if you have a DocumentWindow which you have closed, it cannot be restored later.

I hope that you find this information useful. 

Greetings,
Stefan
the Telerik team