Configuration Variables dialog should have:
Favourites Category.
Textbox where we type the variable should be a ListBox instead to show Recent Variables (similar than key-in window with a triangle icon).
If we type "MS_DGNLIBLIST, if it was able to right-click on a path and the context menu has "Open Folder", to open the folder. Similar as we can do with "Open an existing file" (CTRL+O) or at least "copy"
Please also make the divider between the left pane and the right pane of the dialog window adjustable. When you drag the edge of the dialog box to be larger, it needlessly expands the left pane instead of just creating more room for the 4 columns in the right pane.