DT is logical in that if you select a group on the LHS, it displays the contents in the upper pane, select a file here & it’s displayed in the main work area below.
I always have at least 6 Tabs open in my work spaces. The files associated with these tabs don’t necessarily come from the same parent group or data base. The result of this, is I can select a tab, but the upper pane shows the contents of a totally unrelated group.
It would greatly increase my usability if by selecting a Tab, the contents of it’s parent group was displayed above, making it easy to select an associated file.