I didn't put this in a bug report, etc. The problem is immune to fixing, going back to Molassas4.
See the image below (photo; I keep the PC off-line). Note the blue-line tab is CNNTS in the lower right corner. In theory, this tab should respond to page up or down. But actually the page up/down is attached to NAB in the upper-left (the active-panel prior to selecting CNNTS). The problem is touching the tab to establish focus is not the same as touching the text area, for attaching focus.
The other focus issue going way back, is a right-click selection of a resource in a layout (which is not showing currently) will not be moved into viewing ... the selected tab remains hidden as if the user really didn't want to actually look at the resource (and thus no highlighted tab visible).
So, it goes.
