How to go back to old MonoDevelop Ctrl-Shift-tab behavior? Should go to "last viewed tab", not "tab on the left of the current one"

I believe MonoDevelop has changed its ctrl-tab and ctrl-shift-tab behavior and I would like to get back to the old behavior, as the new way frustrates my workflow.

Previously, I could follow a class definition by hitting F12. Here's a diary entry from when it worked well:

I hit F12. MonoDev jumps to the relevant tab with the definition I wanted to check. If it wasn't open already, it would have opened it. But I don't need to pay attention to how it gets me to the class definition. Because I know at any time I can simply hit Ctrl-Shift-tab. I hit Ctrl-Shift-tab. I'm back to where I was. I can continue my work.

But today that doesn't happen. Here's a journal entry from today:

Today ctrl-shift-tab takes me to whichever tab happens to be to the left of the one F12 took me to. I have no interest in that tab to the immediate left, and now I am lost. I cannot remember where I was. I don't know from which tab I came. I go back into Unity to help me remember. I start toying with color schemes. Please, please help me.

Is there a way to make shift-ctrl-tab do what it previously did, or is there another shortcut which fills this roll? I can't find anything in the settings and googling has not got me anywhere.