Currently both the app switcher and the thumbnail list divide items
first into two groups (based on whether the item is located on the
current workspace or not), and then sort each group individually
by MRU.
The resulting behavior is often confusing, e.g. when using alt-tab
a second time does not switch back to the original window when the first
invocation involved a workspace switch and the workspace contains
windows of more than one application.
Instead, make the behavior more predictable by sorting both lists
strictly by MRU.
https://bugzilla.gnome.org/show_bug.cgi?id=661156
b50702dd52